It's finally happened. After years, if not decades, of warnings about Japan's aging population and its low birth rate, the day is here. Japan's official census shows that the country's population has shrunk.

And not by an inconsiderable amount either: The 2010 census showed a population of 128,057,352, but the 2015 figure, released Friday, shows just 127,110,000.

Japan's population had shrunk by almost 1 million people in five years.

While data on birth and death rates has long given clear evidence that Japan's population was on the decline, this is the first time since records began that the census has confirmed the nation's population has actually dropped (the blip between 1940 and 1950 in the chart is largely due to the fact that many Japanese soldiers were stationed abroad and Okinawa island, then controlled by the United States, was not included in the census).

The following chart, which shows the population change between each census since 1950, gives a sense of just how dramatic an effect Japan's dwindling demographics are having:

So does this come as a surprise to anyone? Nope, not at all. Almost a decade ago, The Washington Post's Fred Hiatt warned that Japan had "embarked on a path no developed nation has ever followed -- of sustained and inexorable population decline."

Japan's birth rate has long been significantly below the 2.1 per woman that is needed to sustain growth — it currently stands at about 1.4 per woman — and the deficit isn't made up by significant levels of immigration like it is in some other nations. Nearly a third of all Japanese citizens were older than 65 in 2015; Research from the National Institute of Population and Social Securities Research suggests that number will rise to 40 percent by 2050.

Japanese Prime Minister Shinzo Abe has said that keeping the population of Japan above 100 million is a priority. However, actually doing that may be difficult. Last year, the Population Division of the U.N. Department of Economic and Social Affairs released a population estimate for Japan that showed the country would dip below 100 million shortly after the middle of the 21st century. By the end of the century, Japan stood to lose 34 percent of its population, the United Nations found.

Japan is far from alone here. The U.N. has estimated that a total of 48 countries will see their population decline by 2050. Moldova is expected to lose more than half its population by 2100, the worst decline of anywhere in the world. But Moldova is tiny. Japan is the third largest economy in the world. It's a crucial trading partner for the United States and China. How exactly will its declining population affect the wider world? Looks like we'll start finding out soon.

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