Washington, Jun. 14 (UPI) — The number of illegal migrants arriving in the United States has exceeded the number of new legal immigrants, a Pew Hispanic Center report finds.

In recent years some 700,000 unauthorized migrants have arrived annually, compared with about 610,000 legal immigrants.

"Unauthorized Migrants: Numbers and Characteristics" was prepared by Jeffrey Passel, a veteran demographer and senior research associate at the center.

The report estimates the number of people living in families in which the head of the household or the spouse is an illegal alien at 13.9 million as of March 2004, including 4.7 million children.

The report also said at least 6.3 million unauthorized workers were employed as of March 2004, comprising 4.3 percent of the civilian labor force.

Overall, illegal migrants are less educated than other sectors of the population, with 49 percent not having completed high school, compared with 9 percent of the native-born and 25 percent of legal immigrants.