Millions of Americans counted in the 2000 census changed their race or Hispanic-origin categories when they filled out their 2010 census forms. Hispanics, Americans of mixed race, American Indians and Pacific Islanders were among those most likely to check different boxes from one census to the next. ** Hispanics are often described as driving up the nonwhite share of the population. But a new study of census forms finds that more Hispanics are identifying as white.