As major political questions about unauthorized immigrants in the United States continue to be debated, the size and nature of the undocumented population is changing. Observers note several new trends that may be driving such changes. Law enforcement tactics and policies are evolving, home country economies are changing, and the negative economic and labor situation within the United States has made the country less attractive to some potential migrants.

A 2011 report by the Pew Hispanic Center, part of the Pew Research Center, “Unauthorized Immigrant Population: National and State Trends,” examines the changes in demographic patterns and characteristics of undocumented border-crossers.

The report’s findings include:

• In March 2010, undocumented immigrants made up 3.7% of the U.S. population and 5.2% of the labor force. As of 2010, the estimated unauthorized population was 11.2 million; this figure remains roughly unchanged since 2009. The overall number has decreased by 8% from 2007, when it peaked at 12 million.
• A large part of the decline is due to a decrease in illegal border-crossing from Mexico. In 2007, 7 million of the 12 million unauthorized immigrants in the United States were Mexican; in 2010, the number of such Mexican migrants had dropped to an estimated 6.5 million.
• On an annual basis, an estimated 150,000 Mexicans migrated illegally to the United States during the period 2007-2009; this represents a 70% decrease from the annual average of 500,000 in the period from 2000-2005.
• Total numbers have gone down not only as a result of decreased border-crossing, but also increased deportations; these have nearly doubled in the past decade, peaking in 2009 at 400,000. On average, 70% of all deportations are of persons of Mexican origin.
• Of the unauthorized immigrant population, Mexicans make up the majority and represent 58%; in second place is a combination of individuals from all other Latin American countries, accounting for 23% overall; in third place are migrants from Asian countries, representing 11% of this population.
• From March 2009-March 2010, 74% of all births were to U.S.-born parents, 17% to legal immigrants, and the remaining 8% to unauthorized immigrants.

The report notes that “although the estimates presented here indicate trends in the size and composition of the unauthorized-immigrant population, they are not designed to answer the question of why these changes occurred.”

Tags: Hispanic, Latino, race, campaign issue