1,010,515 (789,997 non-Hispanic white, 62,408 African-American, 90,642 Hispanic, 49,867 Asian, and 17,601 Native American) women, 40 years of age or older, who had undergone mammography at least 1 time between 1996 and 2002 at a location that reported to 1 of 7 possible mammography registries.