The U.S. foreign-born population has reached a record high, though the rate at which people came to America has slowed considerably, the government reported Monday.

Experts suggest that downward trend may be due partly to the faltering economy and fallout from the Sept. 11 terrorist attacks.

According to Census Bureau estimates, there were about 32.5 million foreign-born residents in the United States in March 2002, 2 percent more than the 31.8 million in the previous March.

In a population of 282.1 million, the foreign born amounted to 11.5 percent.

The growth rate had been three times greater between March 2000 and 2001.

About 1.2 million people arrived in the country in the 12 months ending in March 2002, compared with 2.4 million the previous year, according to demographer William Frey, who analyzed the figures.

Besides new arrivals, the estimates also account for deaths and those who left the United States.

The government worked to close immigration loopholes and provide closer scrutiny of those admitted to the country after the Sept. 11 attacks. That, coupled with a slowing economy, may have caused some would-be immigrants to stay home, said Frey, who works at the Brookings Institution, a Washington think tank.

But Frey and other experts said other factors also played a role.

For instance, immigration officials in 2001 reduced a yearslong backlog in visa applications, which could have led to an artificially high number of new immigrants, said Angela Kelley, deputy director of the National Immigration Forum, an immigrant advocacy group.

The Census Bureau surveyed 85,000 households last March. As in political polls, the census estimates have margins of error that mean the actual results may be slightly higher or lower.

Still, there is ample evidence for a decline, though it is likely a temporary blip, said Steven Camarota, research director at the Center for Immigration Studies. For many immigrants, concerns over the recession and government crackdowns pale in comparison to the desire to seek a better life in America.

"You would have to change policy and begin a vigorous enforcement effort across the board in order to reduce immigration," said Camarota, whose group favors more curbs on immigration.

Groups such as the National Immigration Forum counter that some enforcement efforts have unfairly targeted thousands of innocent immigrants, especially those of Middle Eastern descent. Arab-American groups have alleged that discrimination against Arabs and Muslims rose after the attacks.

California long has been considered a bellwether for immigration trends. While there was no state data available from the latest census report, typically the flow of migrant workers in and out of the state slows when the economy falters, said Hans Johnson, a demographer specializing in immigration studies at the Public Policy Institute of California.

"If anything, Sept. 11 would have a short-term effect on immigration. Any long-term decline would more strongly be related to the economy," Johnson said.

A Northeastern University study released last year said immigrants accounted for more than half the growth in the labor force between 1990 and 2001, filling openings in factories, textile mills and other blue-collar industries.

Among the other highlights from the census report:

--Nearly 17 million people, or just over half of the foreign-born population in 2002, came from Latin America. Over half of the 17 million arrived after 1990.

--Slightly more than one-quarter of the foreign-born population had a bachelor's degree or more, about the same as the native-born population. More than 20 percent of the foreign-born population had less than a ninth-grade education, compared with about 5 percent of the native population.

The census report did not count immigrants in jails, nursing homes or other group quarters, and did not cover illegal immigration.

A separate report released in January by the Immigration and Naturalization Service estimated an illegal immigrant population of roughly 7 million, growing about 350,000 a year during the 1990s. Mexicans made up almost 70 percent of the illegal immigrant population in 2000, the INS said.