This is the second of three study reports on the national incidence of child care usage as well as consumer needs, preferences, attitudes and opinions on child care, based on 4609 personal interviews conducted in 1975 from a national probability sample of households with children under 14 years of age. The study was sponsored by the Office of Child Development of the U.S. Department of Health, Education and Welfare. This volume reports the prevalence of use among various types of child care, describes the population subgroups who use care, and provides an analysis of the patterns and trends of usage. Data are organized under the following headings: (1) Sampling Methodology and Design, (2) Analytic Framework, (3) Simple Incidence of Usage, (4) Hours Used Per Capita: A Summary Usage Index, (5) Characteristics of Substantial Users, (6) Payment Mode and Formality of Care, (7) Costs of Child Care, (8) Transportation Arrangements, and (9) Summary Discussion and Conclusions. (MS)