Census 2000 counted approximately 281 million people. The majority were counted via a mailed questionnaire. Approximately 550,000 enumerators conducted door-to-door interviews only for households that could not be reached by the U.S. Postal Service or did not return their mailed questionnaire. The instructions provided here were used by enumerators who visited households that did not return their mailed questionnaire during Census 2000's "Nonresponse Follow-up" (NRFU) operation.