Boy or girl, prince or pauper, no one knows — but the 300 millionth American is expected to arrive at about 7:45 am (11:45 GMT), October 17, the US Census Bureau announced Thursday. The Census Bureau has for years calculated one birth of a US citizen every seven seconds, one death every 13 seconds and a nationalized citizen every 31 seconds, and will chalk up the 300 millionth on Tuesday.

The 300 million mark comes just 39 years after the odometer rolled over to 200 million, making the United States the only industrialized country with strong population growth.

At the time in 1967, the US population was 84 percent white, 11 percent black, four percent Hispanic and one percent Asian and Pacific islander, according to the Pew Hispanic Center.

Today about 67 percent are white, 13 percent black, 15 percent Hispanic and 5 percent Asian, according to center figures.

Of the 100 million added to the population in the last four decades, 36 percent were Hispanic, the most of any racial or ethnic group, according to the Pew Hispanic Center.

"Immigration from Latin America and relatively high fertility rates among Latinos were major factors in this increase," it said.

The world's third most populous country behind China and India, the United States has five percent of the world's population.

Source: Agence France-Presse