The population of Mexican-born persons residing in the United States
has increased at an unprecedented rate in recent decades. This increase
can be attributed to both legal and illegal immigration. During the entire
decade of the 1950s, only about three hundred thousand legal Mexican immigrants
entered the United States, making up 12 percent of the immigrant
flow. In the 1990s, 2.2 million Mexicans entered the United States legally,
making up almost 25 percent of the legal flow (U.S. Immigration and Naturalization
Service 2002). In addition, it is estimated that (as of January
2000) there were 7 million illegal aliens residing in the United States, with
4.8 million (68 percent of this stock) being of Mexican origin (U.S. Department
of Commerce 2004). As a result of the increase in the number of legal
and illegal Mexican immigrants, nearly 9.2 million Mexican-born persons
resided in the United States in 2000, comprising about 29.5 percent of the
foreign-born population (U.S. Bureau of the Census 2003).