Estimates of the Size and Characteristics of the Undocumented Population
- Following several years of steady growth, the number of undocumented residents reached an estimated 10.3 million in March 2004 with undocumented Mexicans numbering 5.9 million or 57 percent of the total.
- As of March 2005, the undocumented population has reached nearly 11 million including more than 6 million Mexicans, assuming the same rate of growth as in recent years.
- About 80 to 85 percent of the migration from Mexico in recent years has been undocumented.
- Since the mid-1990s, the most rapid growth in the number of undocumented migrants has been in states that previously had relatively small foreign-born populations. As a result, Arizona and North Carolina are now among the states with largest numbers of undocumented migrants.
- Although most undocumented migrants are young adults, there is also a sizeable childhood population. About one-sixth of the population—some 1.7 million people— is under 18 years of age.