There are more than 35 million people in the U.S. who were born in other countries, including an estimated 11 million to 12 million illegal immigrants.

Some figures on illegal immigrants, from the Pew Hispanic Center:

• Illegal immigrants make up about 5 percent of the U.S. labor force. More than nine in 10 illegal immigrant men are part of the labor force, compared with 83 percent of men born in the U.S.

• Nearly two-thirds of the children in illegal immigrants' homes were born in the United States, making them U.S. citizens.

• Three in four illegal immigrants come from Latin America, a little more than half from Mexico. About a quarter enter the United States legally and overstay their visas.

Some figures on all immigrants, from the private Center for Immigration Studies:

• Immigration, both legal and illegal, continues to boom, with the nation's foreign-born population hitting 35.2 million people in 2005.

• About 12.1 percent of the U.S. population was born in another country, the highest percentage since 1920.

• About 7.9 million people moved to the United States in the past five years, the highest such period on record.

• Mexico is the largest supplier of immigrants to the United States, followed by East Asia, Europe, the Caribbean, Central America and South America.