CEPA estimates the population of undocumented immigrants in Delaware to be 20,250 as of 2008. This includes 14,880 undocumented immigrants in New Castle County, 2,225 in Kent County and 3,150 in Sussex. These estimates are derived from the latest Bureau of Census data on the foreign born population for Delaware and the counties. Based upon research by the Urban Institute, 26% of the foreign born population is considered to be undocumented immigrants. That number is then adjusted upward based upon research from the Pew Hispanic Center that finds that the undocumented immigrants from the reported BOC data capture only 85% of all the undocumented population. Application of this same methodology to the whole U.S. results in an estimated undocumented population of 11.5 million, a number very similar to the most cited estimates.