Net Immigration From Mexico Falls To Zero - Possibly Less

The largest wave of immigration from a single country in the history of the United States has come to a halt, according to a report by the Pew Hispanic Center.

In the past 40 years, more than 12 million Mexicans came to the U.S. But that migration flow has stopped - and possibly reversed, according to the report released today.

The flagging U.S. economy, stepped-up border enforcement, and a rise in the number of deportations, and the growing dangers associated with crossing the border all may play a role in the drop off.

The wave of immigration from Mexico could resume when the economy recovers, the report said. But whether or not that happens, the migration over the southern border has already been one for the record books.

The 12 million Mexicans living in the U.S. make up nearly 30 percent of the country's immigrants, according to the report. Indians represent the second largest share of immigrants, accounting for less than five percent of the 40 million immigrants currently living in the country.

The most distinctive characteristic of the Mexican influx - besides its size - is the percent of people who came illegally, the report points out. Just over half of all Mexicans living in the U.S. are doing so without the government's permission. And nearly 60 percent of all illegal immigrants are Mexican.

The decline in migration from Mexico began about five years ago and has lead to the first decline in 20 years in the number of illegal immigrants from Mexico living in the U.S. In 2007, nearly 7 million unauthorized Mexicans lived here. In 2011, that number had dropped to 6.1 million.

At the same time, the number of Mexicans entering legally increased slightly, from 5.6 million in 2007 to 5.8 million in 2011.

Between 2005 and 2010, 1.4 million of Mexicans migrated to the U.S. That is less than half the 3 million who came between 1995 and 2000. At the same time, the number of Mexicans and their children who moved from the U.S. to Mexico rose to 1.4 million.

The majority of the people who left the U.S. for Mexico since 2005 did so voluntarily. But those who were deported and remained in Mexico represent a significant minority.

The center said that although data on the number of Mexicans sent home against their will is somewhat murky, estimates based on government data from both countries suggest that 5 percent to 35 percent of those who left for Mexico may not have left voluntarily.