By Michael Jay Friedman
Washington File Staff Writer

Washington - The U.S. Census Bureau estimates that total U.S. population will reach 300 million in October. Immigration, especially from Latin America and Asia, drives much of this growth and promises to reshape the United States as a more diverse nation, and one where the average age will increase more slowly than in most other industrialized nations.

The Immigration and Naturalization Services Act of 1965 abolished national-origin quotas fixed in the 1920s and opened the nation's shores to new immigrants. Today, the United States accepts more legal immigrants as permanent residents than the rest of the world combined.

The Census Bureau Web site includes a “population clock” that projects the U.S. population as of October 3 to be 299,895,404, with a net gain of one person every 11 seconds.

The foreign-born now comprise 12 percent of Americans. Together with their U.S.-born children, they now account for more than half of U.S. population growth. One result is that Hispanic Americans have become the nation's largest ethnic or race minority, with a population estimated at 42.7 million in 2005. Fourteen percent of Americans were of Hispanic extraction, a figure expected to increase to nearly 25 percent by mid-century.

Asian-born residents comprise one-fourth of the nation’s total foreign-born population, and China is the second largest (after Mexico) country of birth for immigrant Americans.

High birthrates among new immigrants promise continued growth and a younger, more diverse nation. The population of the United States is projected to increase to 400 million by 2043, even as developed nations in Asia and Europe experience declines in population. Today's median age of 36.5 years is expected to reach 39 by 2030 and then level off, a much smaller increase than projected for many other nations.

American schools are one place where the future already has arrived. Smithsonian magazine reports that nearly half of Americans under the age of 5 belong to a racial or ethnic minority. In Fairfax County, Virginia, outside Washington, public schools accommodate students of more than 100 native tongues.

The nation's ability to accommodate both socially and economically these newest Americans is crucial to its continued prosperity and growth.

Journalist Joel Garreau predicts that the "melting pot" model, in which new arrivals blend into the broader American culture while retaining their distinctive identities, will continue to prevail. "New immigrants usually do not marry outside their ethnic group; their adult children do, with some controversy, and their adult grandchildren can't remember what the fuss was about," he writes.

Brookings Institution demographer William H. Fry believes that both consequences of high immigration - growth and diversity - are beneficial. Even as other nations undergo "extreme aging for the most part," the United States will enjoy continued "growth and vitality," he said on a Council of Foreign Relations podcast.

Fry argues that greater racial and ethnic diversity is a "good strategy." It "gives us more connections to other countries. We're living in a global economy where the more ideas we get from other parts of the world, the more interaction we have … the more that these people from other parts of the world are part of our labor force … helps us," he said.

The Census Bureau’s U.S. population clock is available on the bureau’s Web site.

For more information, see Population and Diversity.