WSJ: births not immigrant cause of US Hispanic surge

In the 1990s, a flood of Hispanic immigrants explained most of the group's population rise. That has changed in recent years. Between 2006 and 2007, about 62% of the increase in Hispanics came from births.

http://online.wsj.com/article_email/SB120959501599257567-lMyQjAxMDI4MDA5MTUwOTE1Wj.html