SEATTLE - A study indicates Washington state has the 10th largest concentration of illegal immigrants nationwide -- and also the highest average household income. The Center for Immigration Studies estimates the number of illegal immigrants at nearly 38 million (37.9 million) nationwide, including 277,000 in Washington.

The think tank in Washington, D.C., favors strong immigration control. According to the group's report, legal as well as illegal immigrants in both the state and the nation use welfare programs at higher rates than native-born citizens. The study also contents that they are twice as likely as natives to be uninsured and to live in or near poverty, and nearly four times as likely to lack a high-school diploma.