En español | Is America really ready for the graying of the nation's fast-growing Hispanic population?

See also: 10 Milestones in Hispanic American Immigration.

It's a demographic shift of seismic proportions: The number of Hispanics 50 and older in the United States is projected to grow from 9 million today (out of a total of 50.5 million) to more than 35 million by 2050. And this will have profound implications for society and for government at all levels.

"It's a great challenge for social services such as Medicare and Social Security, since we're talking about a population segment with high levels of inadequate education and low income," says William Vega, a professor at the University of Southern California and executive director of its Edward R. Roybal Institute on Aging. "Many of the older Hispanics will depend on a network of social services, and we don't know if these will be available in adequate levels to meet their needs."

Hispanics make up about 16 percent of the U.S. population, according to the U.S. Census Bureau, and by 2050 are expected to make up 30 percent of the population — a virtual doubling.

From 2000 to 2009, the number of Hispanics 50-plus nationwide increased 65 percent. That's much higher than the overall growth rate of the nation's Hispanic population in the same period (36 percent) and the growth rate of the nation's overall 50-plus population (24 percent).

Little wonder, then, that demographers and policymakers are paying close attention. Melanie Deal-Concepción of the Census Bureau points out, for example, that the agency's data help "the government to allocate resources for services such as health and education."

Waves of Latin American Immigration

The first great wave of Latin American immigration in the 20th century came during World War II. As American workers went off to war, the nation experienced serious labor shortages, and Hispanics were among those who stepped in to keep wartime production going.

The next big wave was from 1980 to 2009 — the highest period of immigration in U.S. history. More than 38 million people born outside the United States lived here during 2009, according to the Census Bureau, and nearly 80 percent of them — more than 30 million, including almost 17 million arrived from Latin America — arrived in that 30-year period.

"The Hispanics who just turned 50 are the ones that started this great migratory wave of Latin Americans to the United States," says AARP consultant Roberto Suro, a former executive director of the Pew Hispanic Center and a professor at the University of Southern California.

Soon they will all be 50-plus. But, as Vega points out, immigration-fueling forces in Latin America have abated in the past few years. "The countries of Latin America are growing faster than the United States," he says, adding that "their economies are providing workers with better opportunities."

Nevertheless, demographic projections suggest that the Hispanic population of the United States will continue to grow because of steady immigration and comparatively high fertility rates.