WASHINGTON — The flow of illegal immigration into the United States has declined in the past few years, a study released Thursday found.
The number of illegal immigrants arriving in the United States has dropped from about 800,000 a year earlier this decade to about 500,000 a year from 2005 to 2008, said the report by the Pew Hispanic Center, a nonpartisan research group in Washington.
The findings reverse a decade-long trend in which more illegal immigrants than legal immigrants arrived in the United States.
“These numbers tell us that the growth has slowed substantially,” said Jeffrey Passel, a demographer with the Pew Hispanic Center and co-author of the study. “This is a population that had been growing rapidly for at least 15 years, and the growth has essentially come to a halt in 2008.”
The total number of illegal immigrants appears to have decreased from 12.4 million in 2007 to 11.9 million in 2008, the study said. However, the finding is “inconclusive” because of the margin of error in the estimates, the study said.
The study did not include any explanations for the decline in the flow of illegal immigrants into the United States, but experts pointed to the struggling economy as a major factor.
The study also found:
• Illegal immigrants comprise about 4 percent of the U.S. population and about 30 percent of the nation’s foreign-born population. More than 39 million people born in other countries live in the United States.
• The vast majority of illegal immigrants — four out of five — come from Latin American countries.
• The number of illegal immigrants from Mexico appears to have leveled off since last year at around 7 million.
Clarissa Martinez, director of Immigration and National Campaigns at the National Council of La Raza, a Latino civil-rights organization, said that the decreased flow of undocumented immigrants is about one thing: the economy.
The sectors where undocumented immigrants are concentrated — such as construction and service industries — were among the first to feel the economic downturn, so it is logical that the flow of people seeking a job would decrease, she said.
But Steve Camarota, director of research at the Center for Immigration Studies, which advocates lower levels of immigration, said that stepped-up enforcement efforts, including a string of large workplace raids by U.S. Immigration and Customs Enforcement, also had a major impact.
“There are two obvious reasons — enforcement and the economy,” he said.
Camarota said that many enforcement efforts, including local ordinances designed to crack down on illegal immigration, are magnified by extensive coverage in Spanish-language media and have acted as a deterrent to illegal immigration.
The Pew Hispanic Center released another report Thursday that seemed to buoy the theory that the economy is causing the slowdown.
It found that the median annual income of noncitizen immigrant households fell 7.3 percent from 2006 to 2007.
By comparison, the income of all U.S. households increased 1.3 percent during the same period.
