While the political debate over immigration reform continues to evolve, underlying patterns of migration to the United States have been shifting in recent years.

A 2012 study by the Pew Hispanic Center, “Net Migration from Mexico Falls to Zero — and Perhaps Less,” uses data from 1850 to 2011 to chart migrations between the two nations, record the experiences of immigrants and analyze the conditions that may affect immigration. The study updates some of the findings in a related 2011 report, “Unauthorized Immigrant Population: National and State Trends.”

The 2012 study’s findings include:

• The Mexican-born population living in the United States grew 23% from 2000 to 2005 to 12 million, peaked in 2007 at 12.6 million, and dropped back to 12 million by 2011. Approximately half of all entries from Mexico each year are unauthorized.
• U.S. Census Bureau data indicate that 700,000 Mexicans a year — both legal and illegal immigrants — came to the United States in 1999-2000 when the U.S. economy was thriving; only 140,000 arrived in 2010. Researchers link the decline to the collapse in the United States’ housing and construction markets that began in 2006. “It may become the first sustained loss [in migration rates] since the 1930s, when the Mexican-born population shrank during the Great Depression”
• The United States Immigration and Customs Enforcement Bureau reports that 88,112 Mexicans were involuntarily returned in 2010. About 17% of these individuals were apprehended at work or home, an increase from 3% in 2005. The percentage apprehended at the border has steadily declined, from 49% in 1995 to 25% in 2010.
• In 2010, 20% of repatriated Mexicans said that they that would not return to the United States; in 2005, only 7% stated no interest in returning.
• “The rising median age in Mexico has meant that its 15- to 39-year-old age group — people in peak years for emigration — has declined as a share of the overall population. In 2010, 15- to 39-year-olds made up 65% of Mexico’s working-age population (defined as all adults between ages 15 and 64). In 1990, this age group comprised 73% of the working-age population.”

The authors conclude that “after four decades that brought 12 million current immigrants (most of whom came illegally), the net migration flow from Mexico to the United States has stopped and may have reversed.”

Tags: campaign issue, Mexico