Somewhere in America, every eight seconds on average, a new baby is born.
Somewhere else, someone dies every 12 seconds.
And every 31 seconds ... the nation adds another immigrant.
Add those numbers up, and the U.S. Bureau of the Census says that sometime this fall, probably in October, the population of the United States will reach 300 million people.
Just who will be No. 300 million, nobody can say. The Census Bureau -- empowered by the Constitution to count us every 10 years -- keeps running figures that show a nation gradually changing.
People continue to move to the South and West. Almost half of all Americans now live within 50 miles of a coastline -- great for people who enjoy going to the seashore, worrisome if future hurricane seasons match last year's.
The population center of the United States -- a theoretical point on which the nation would balance if it were a giant, flat board -- is now in Phelps County, Mo., 2.8 miles from the town of Edgar Springs (population 190 in the 2000 census). The spot has steadily moved west and south as people move to Sun Belt states (the population center was in eastern Maryland in the 1790 census). But there's an irony at work: Many Midwestern states continue to lose people, despite some ambitious efforts to attract new homesteaders.
The population is actually growing quite a bit slower than one might suspect. Growth is down to about 1 percent per year, or 2.8 million people. Other wealthy countries, in Western Europe and the Pacific Rim, are losing population.
The nation has changed substantially since 1967, when the population clock in the lobby of the Census Bureau in Washington passed 200 million. There has been dramatic growth in the minority population, especially among Hispanic and Asian-Americans.
In the 1970 census, 83.5 percent of the population was labeled white. That has dropped to 67.4 percent, according to the census. The Hispanic percentage has grown from 4.5 percent to 14.1 percent, and the Asian portion of the population has grown from 0.8 percent to 4.1 percent. Those categorized as black have remained proportionally about the same, growing from 11.1 percent to 12.2 percent.
So what might the symbolic 300-millionth American be like? If it's a baby, as opposed to an immigrant, he or she is likely to be conceived in the next month or so. The chances have increased that the new American will come from a Spanish-speaking household, and that one parent or another will be an immigrant. In the 1970 census, 4.7 percent of Americans were foreign-born; in 2004, that number grew to 12 percent.
One other well-known trend: Americans are living longer. In 1900, a newborn baby could expect, on average, to reach age 47. In 2004, that had risen to 77.8.
We cannot know who the 300-millionth American will actually be -- just that he or she will have plenty of company.