Analyzes migration streams between metropolitan and nonmetropolitan areas, 1975-93, in terms of sex, race, age, educational attainment, poverty level, and occupational status. Distinct shifts included nonmetro gains and retention of the young and better-educated during the 1970s, loss of those groups in the 1980s, and increased nonmetro population retention during the early 1990s. Contains 34 references. (SV)