Prior to 1829, the area of modern day Greece was largely under the control of the Ottoman Empire. In 1821, the Greeks declared their independence from the Ottomans, and achieved it within 8 years through the Greek War of Independence. The Independent Kingdom of Greece was established in 1829 and made up the southern half of present-day, mainland Greece, along with some Mediterranean islands. Over the next century, Greece's borders would expand and readjust drastically, through a number of conflicts and diplomatic agreements; therefore the population of Greece within those political borders** was much lower than the population in what would be today's borders. As there were large communities of ethnic Greeks living in neighboring countries during this time, particularly in Turkey, and the data presented here does not show the full extent of the First World War, Spanish Flu Pandemic and Greko-Turkish War on these Greek populations. While it is difficult to separate the fatalities from each of these events, it is estimated that between 500,000 and 900,000 ethnic Greeks died at the hands of the Ottomans between the years 1914 and 1923, and approximately 150,000 died due to the 1918 flu pandemic. These years also saw the exchange of up to one million Orthodox Christians from Turkey to Greece, and several hundred thousand Muslims from Greece to Turkey; this exchange is one reason why Greece's total population did not change drastically, despite the genocide, displacement and demographic upheaval of the 1910s and 1920s. Greece in WWII A new Hellenic Republic was established in 1924, which saw a decade of peace and modernization in Greece, however this was short lived. The Greek monarchy was reintroduced in 1935, and the prime minister, Ioannis Metaxas, headed a totalitarian government that remained in place until the Second World War. Metaxas tried to maintain Greek neutrality as the war began, however Italy's invasion of the Balkans made this impossible, and the Italian army tried invading Greece via Albania in 1940. The outnumbered and lesser-equipped Greek forces were able to hold off the Italian invasion and then push them backwards into Albania, marking the first Allied victory in the war. Following a series of Italian failures, Greece was eventually overrun when Hitler launched a German and Bulgarian invasion in April 1941, taking Athens within three weeks. Germany's involvement in Greece meant that Hitler's planned invasion of the Soviet Union was delayed, and Hitler cited this as the reason for it's failure (although most historians disagree with this). Over the course of the war approximately eight to eleven percent of the Greek population died due to fighting, extermination, starvation and disease; including over eighty percent of Greece's Jewish population in the Holocaust. Following the liberation of Greece in 1944, the country was then plunged into a civil war (the first major conflict of the Cold War), which lasted until 1949, and saw the British and American-supported government fight with Greek communists for control of the country. The government eventually defeated the Soviet-supported communist forces, and established American influence in the Aegean and Balkans throughout the Cold War. Post-war Greece From the 1950s until the 1970s, the Marshall Plan, industrialization and an emerging Tourism sector helped the Greek economy to boom, with one of the strongest growth rates in the world. Apart from the military coup, which ruled from 1967 to 1974, Greece remained relatively peaceful, prosperous and stable throughout the second half of the twentieth century. The population reached 11.2 million in the early 2000s, before going into decline for the past fifteen years. This decline came about due to a negative net migration rate and slowing birth rate, ultimately facilitated by the global financial crisis of 2007 and 2008; many Greeks left the country in search of work elsewhere, and the economic troubles have impacted the financial incentives that were previously available for families with many children. While the financial crisis was a global event, Greece was arguably the hardest-hit nation during the crisis, and suffered the longest recession of any advanced economy. The financial crisis has had a consequential impact on the Greek population, which has dropped by 800,000 in 15 years, and the average age has increased significantly, as thousands of young people migrate in search of employment.

From 1856 until 1907 both the male and female populations of Greece grow at a similar rate, with the number of men remaining slightly higher than women, the largest difference being 100 thousand people in 1896. This difference drops to just 18, thousand eleven years later, and from the next entry onwards the number of women is always larger than the number of men. This change in demographics is due to large changes in Greece's borders, with the population almost doubling in size between 1900 and 1950, as well as a number of major wars and civil unrest which had an unproportionate effect on the number of males. There were approximately 100,000 more males than females at the turn of the century, however this difference had flipped by 1950 where there was then over 200,000 more females than males.

From the 1950s onwards, the proportional difference in male and female populations decreases and the difference decreases to just 66 thousand in 2000. Both populations grow steadily throughout this time but then decrease together between 20110 and 2020. This This sudden decline is due to the economic impact on the Greek economy during the Great Recession. Many Greeks have left the country in search of work elsewhere, and the economic troubles have impacted the financial incentives that were previously available for families with many children, both factors contributing to a predicted population of 10.4 million in 2020, which is almost half a million lower than it was ten years previously. The proportional difference between men and women also increased during this time, and there are over 190 thousand more females than males in Greece in 2020, as men are statistically more likely to emigrate in search of work abroad.

In 1800, the region of present-day Turkey had a population of approximately 9.8 million. Turkey’s population would grow steadily throughout the 1800s, growing to 14 million by the turn of the century. During this time, Turkey was the center of the Ottoman Empire, which also covered much of the Balkans, Arabia, and the African coast from Libya to Somalia. In the early 20th century, the Ottoman Empire's dissolution period began, characterized by political instability and a series of military defeats and coups. The empire was one of the defeated Central Powers of the First World War, in which it suffered approximately three million total fatalities. It is estimated that the majority of these deaths did not come directly from the war, but as a result of the government-orchestrated mass expulsion and genocide of non-Turks from within the Turkish borders, specifically Armenians, Assyrians, Greeks and Kurds; many ethnic Turks were simultaneously expelled from neighboring countries, namely Greece, which makes these events less-visible when examining annual data, although Turkey's total population did drop by one million between 1914 and 1924.

The Republic of Turkey Following the end of the Turkish War of Independence in 1923, and the establishment of the republic of Turkey, the population would begin to recover, tripling from just around 21 million in 1950 to over 63 million by the turn of the century. The new republic, led by Mustafa Kemal Atatürk, introduced sweeping, progressive reforms that modernized the country, particularly its healthcare and education systems. Turkey remained neutral throughout the Second World War, and became a member of NATO during the Cold War. The second half of the 1900s was marked with intermittent periods of political instability, and a number of military conflicts (namely, in Cyprus and Kurdistan). In spite of this, Turkey has generally been considered a developed country for most of this time, although its life expectancy and infant mortality rates have often been more in line with developing nations.

Modern Turkey In the past decade, Turkey's population growth has continued its rapid growth; while birth rates have declined, the mass migration of refugees to the country fleeing the Syrian Civil War has seen the population growth ramain high. This influx of refugees was seen as a stepping stone in Turkey's accession to the European Union, with whom it has been negotiating a potential membership since 2005. Accession to the EU would provide huge economic benefits to Turkey, however, political developments in recent years (particularly the 2016 coup) have seen these negotiations stall, as the EU has accused the Turkish government of committing widespread human rights violations, such as torture, political imprisonment and censorship of free speech. In 2020, Turkey's population is estimated to be over 84 million people, and is expected to exceed 100 million in the next two decades.

In 1800, the region of modern-day North Macedonia had a population of approximately 392,000. The population grew steadily throughout the 19th century, and reached approximately 800,000 by the beginning of the 20th century. During this time the region was under Ottoman control, and was something of an ethnic melting pot, with significant shares of the population made up of Macedonians, Greeks, Turks, as well as other Slavic groups. The early-1900s saw control of the region pass between various powers, as the Ottoman Empire fell and gave way to a power vacuum in the Balkans. Following the Second World War, North Macedonia became a part of Yugoslavia; the war's end would also see a baby boom, along with increased population growth throughout the second half of the 20th century.

The gradual dissolution of Yugoslavia in the early 1990s gave way to the establishment of an independent Macedonia in 1991. This time also saw much emigration from the region, both within the former-region of Yugoslavia, as well as abroad; international migration was largely driven by economic factors, especially due to those associated with independence, as well as those associated with the strained political relationship with Greece. Disputes with Greece over the terms "Macedonia", "Macedonians", and their cultural significance, resulted in Greece blocking the country's applications to join the EU and NATO. Non-membership of both these organizations prevented the country from obtaining the associated socio-economic benefits for decades, before a referendum was held in 2018 to officially change the name to the "Republic of North Macedonia". Since this time, Greece has withdrawn its objections to North Macedonia's accession to the the EU and NATO, and the relationship between the two has improved. North Macedonia became a member of NATO in March 2020, however disputes with Bulgaria arose in November of the same year, which have further delayed accession to the EU. Over the past two decades, North Macedonia's population has grown, although it has remained fairly constant at just over two million people.

Albania, then known as Rumelia, was a province of the Ottoman Empire from the fifteenth century until it declared it's independence in 1912. Following a series of unsuccessful uprisings and brief occupations from nearby Serbia and Greece, Albania finally claimed its independence on November 28, 1912; however the Conference of London in 1913 then set the borders of the former-Ottoman states in Southern Europe, which left many ethnic Albanians living in other neighboring states, particularly Serbia (and what is now Kosovo). The newly-formed Albanian state collapsed in the wake of the First World War, and was controlled in parts by Greece, Italy and Serbia. The Paris Conference then established an independent Albanian state, which led to a period of political and economic turmoil that lasted until Italy's annexation of the region in 1939, during the Second World War. It is estimated that just under 3 percent of Albania's population perished as a direct result of the war, as Albania became the main theater for the Axis Powers' war against Greece. Italy then surrendered control of the area to Germany in 1943, and after the war ended in 1945, Albania became a Yugoslav satellite state and remained behind the Iron Curtain until it's collapse in the 1990s. Steady growth during the communist era From the war's end onwards, Albania's population enjoyed steady growth and almost tripled by 1990. Throughout this time, Albania underwent a series of political allegiances; first as a Yugoslav and then Soviet satellite states, but then became an important actor in the Sino-Soviet split, eventually siding with China in the 1960s. Gradually, Albania transitioned into a more isolationist and independent country in in the 1970s, and slowly adopted some more democratic practices. The total population surpassed two million people in the late 1960s, and three million in the late 1980s, but then a dramatic change in population growth occurred in the 1990s, as communism in Europe came to an end. Immediate decline following communism's end Increased freedom of movement, improved access to contraception and major lifestyle changes caused the population to fall into decline. The population did increase in the late 90s, despite a civil war in the first half of 1997 (in which over 2 thousand people died) sparked by a failure of the financial system in Albania. The Albanian Army was also involved in the war in neighboring Kosovo between 1998 and 1999. The 2000s brought about further decline, and the population is just 2.9 million in 2020, a decline of approximately 400,000 people in thirty years. Albania has been a candidate for accession to the EU since 2014, and membership would bring further change to the country.

Bulgaria, with the help of the Russian Empire, achieved independence from the Ottoman Empire in 1878. In the decades before independence, Bulgaria's population had remained between 2.2 and 2.8 million people, and growth was much slower then the following century. Although most at the time assumed that it would become a Russian ally, Bulgaria defied the expectations and aligned itself with the western powers, and developed into a modern European state by the turn in the late 1800s. Bulgaria at war In the early twentieth century Bulgaria was involved in both World Wars, as well as two Balkan Wars. The Balkan states were unhappy with the borders assigned to them by the western powers, and instead wanted to re-draw them based on the dispersal of ethnic groups. This led to the first Balkan War in 1912, which saw Bulgaria fight alongside Greece and Serbia against the Ottomans. Bulgaria fought the second Balkan War on all sides, this time against Greece, Serbia, Romania and the Ottomans, as the dispute over borders continued. Bulgaria was defeated this time, and sustained heavy casualties, amassing in 58 thousand fatalities and over 100 thousand wounded in the two wars.

In the First World War, Bulgaria remained neutral at first, in order to recover from the previous wars, but then aligned itself with the Central powers in 1915, and played a vital role in maintaining their control in the Balkans. While Bulgaria was initially successful, its allies weakened as the war progressed, and then Bulgaria eventually succumbed to Allied forces and surrendered in 1918, with almost 200 thousand Bulgarians dying as a result of the war. The interwar years was a period of political and economic turmoil, and when control was re-established, Bulgaria was then able to maintain it's neutrality throughout most of the Second World War, (although there was some conflict and bombings in certain areas). Rise and fall of communism After the war, Bulgaria became a communist state, and life became harsh for the civil population there until the late 1950s when the standard of living rose again. In the late 1980s, like many Eastern European countries, Bulgaria experienced economic decline as the communist system began to collapse. Political failures also contributed to this, and approximately 300 thousand Bulgarian Turks migrated to Turkey, greatly weakening the agricultural economy. This trend of mass migration abroad continued after the fall of the iron curtain, as well as the rise of unemployment. Bulgaria reached it's peak population size in 1985 at 8.98 million inhabitants, but then the number decreases each year, and is expected to be 6.94 million in 2020. This drop in population size has been attributed to the economic collapse at the end of communism in Eastern Europe, causing many to leave the country in search of work elsewhere. Bulgaria also has one of the lowest fertility rates in the world, with 8.7 births per 1,000 people per year (in 2018).