And Counting . . . : Latest census resets U.S. population clock

The 2000 census missed a little more than 1 percent of the nation’s population, according to follow-up surveys conducted by the U.S. Census Bureau. One of the biggest contributors to the error was a surge of undocumented immigrants to the United States in the late 1990s. Nevertheless, the undercount was far less than the bureau’s researchers and others expected it to be.