The news: For the fifth consecutive year, protestors marched through Chicago on May Day in support of immigrant rights.

Behind the news: Within the span of the past three presidential elections, the number of foreign-born citizens saw a large increase in Cook County. The number climbed 19 percent from 420,739 in 2000 to 501,908 in 2008, according to a Chicago Reporter analysis of census data. A major source of that growth comes from suburban Cook County, where the number of foreign-born citizens increased 37 percent to 269,696 in 2008 from 196,755 in 2000.

“In some areas of Chicago and suburban Cook County, foreign-born citizens have reached a critical mass, and they’re past a tipping point,” said Rob Paral, a former senior research associate at the National Association of Latino Elected and Appointed Officials and a long-time researcher on immigration issues. “It’s become increasingly harder for candidates to ignore immigrant concerns on all kinds of issues, be it schools, government services or police policies.”

The trend in Cook County is consistent with higher naturalization rates observed across the country. Of the 38 million foreign-born people in the country in 2008, about 16 million, or 43 percent, were naturalized citizens, the Reporter analysis shows. More than half became citizens in 1996 or later.

“It is more desirable than ever to be a citizen because the penalties of being a noncitizen are more serious now,” Paral said.