(Undated) -- Many legal immigrants in Illinois and across the country aren't pursuing citizenship. Even though more than eight million nationwide are eligible to apply, many have never even taken the first step. Some immigrants cite the expense, which is about 700-dollars in fees, plus the cost of a lawyer. Others worry they don't speak English well enough to pass the citizenship test. Mark Lopez is with the Pew Hispanic Research Center. He says there are some key differences between having legal permanent status and being a U.S. citizen. A recent Pew Research Center poll found only 36-percent of Mexicans who are here legally actually go on to become naturalized U-S citizens. This percentage is much less than that for other groups, including Cubans, Indians and Europeans.