An observation window enables visiting fathers to look at their newborn offspring at the North Shore Hospital in Sydney in 1956. (Dennis Rowe/BIPs/Getty Images)

Researchers with the Applied Population Lab at the University of Wisconsin at Madison were looking at birth and mortality data when they noticed that a tipping point had been reached: More white Americans died in 2016 than were born.

This wasn’t a surprise, as such. In 2015, there were about 6,600 more births than deaths among whites (technically, non-Hispanic whites), and the gap between the two figures had been narrowing quickly. Regardless, it was another benchmark passed in the shifting demographics of the United States.

The central causes were relatively straightforward.

“More widespread natural decrease results from declining fertility due to the Great Recession, and the aging of the large baby-boom cohorts born between 1946 and 1964,” researchers Rogelio Sáenz and Kenneth M. Johnson wrote. But, they noted, this was affecting whites more than other groups. “Much of this aging baby-boom population is white; so white mortality is growing.”

We can compare those groups. Among Hispanics, the annual number of births has held fairly steady while the number of deaths began to increase only recently.

The two graphs at the bottom, though, show the stark change: The number of Hispanic births has outpaced the number of Hispanic deaths by at least 700,000 since the year 2000. White births haven’t outnumbered white deaths by more than 403,000 in any year.

Among black Americans and Asian Americans, there is also a wide gap. There were 1.8 times as many black births as deaths in 2016 and 4.1 times as many Asian American births as deaths. (The figure for Hispanics was 4.9 times.) The net change among black Americans has been larger than that among whites for each of the past seven years.

The point about the recession is important. The gray boxes on the chart below indicate the change in the number of births and deaths between 2007-2008, 2008-2009 and 2009-2010 — the period of the recession and its immediate aftermath. Among whites and nonwhites, the number of births fell during each of those periods. During and after the recession, the number of deaths crept upward. Again, this is in part because 2010 was the point after which the oldest baby boomers started hitting 65.

It’s hard not to notice, though, that the flip in the white birth-death ratio happened the same year that Donald Trump ran a campaign that was explicitly about restoring the cultural norms of a period in which whites made up a far greater portion of the population. Trump’s campaign rhetoric focused on issues of race, generally indirectly, but the centrality of immigration to his message was itself a commentary on America’s changing demographics.

In 2016, 2.09 million white people were born, and 2.13 million died. Among nonwhites (here restricted to blacks, Asian Americans and Hispanic Americans), 1.78 million people were born, while about 583,000 died, according to data from the Centers for Disease Control and Prevention.

On net, setting aside other factors such as immigration itself, the nonwhite population grew by 1.2 million people, while the white population shrank by 40,000 — the widest divergence between those two numbers since 1999.

The government projects that by 2050, the United States will be both much older and much less white, thanks largely to growth in the Hispanic population. We created this graph several years ago.

That was before Trump’s election. In February, The Post’s Jeff Stein and Andrew Van Dam reported that Trump’s proposal to slash immigration rates could tack on five more years to the existence of the white majority in the country.

If white Americans continue to die faster than they reproduce, though, a majority-nonwhite America is inevitable.