Data from this report on sources of new teachers in the United States are from the 1987-88 and 1990-91 Schools and Staffing Survey (SASS) of the National Center for Education Statistics, a multilevel linked survey of public and private schools, school districts, principals, and teachers. As fewer college graduates enter teaching, concerns have risen about possible teacher shortages. The SASS provides information to help in educational planning. In 1990-91, 177,000 teachers were newly hired in the nation's schools, an increase of 33% over 1988. These new hires accounted for 6% of the public teacher workforce and 13% of the private teacher workforce. Between 1988 and 1991 the sources of newly hired teachers shifted as both public and private schools hired relatively fewer reentrants, teachers returning after a break in service, and relatively more first-time teachers. First-time teachers represented about 53% of all public school new hires in 1991, with about 34% being newly prepared teachers and 19% being delayed entrants to teaching. Transfers from other teaching jobs supplied 16% of public and 22% of private new hires. (Contains 3 figures, 18 tables, and 22 references.) (SLD)