This report presents detailed data on national private school enrollment and tuition trends, collected primarily from governmental sources. Six tables and three figures provide statistical data. An overview describes the availability and analysis problems concerning these data, for example, the lack of information on increasingly attended non-Catholic religiously affiliated schools. Data analysis includes total enrollment (with trends from 1970-85), proportion of students attending private schools, with attendance by region and metropolitan status. Private school students' are charted by family income, control of school (e.g., religiously affiliated), attendance, parental educational attainment, and race/ethnicity. Tuition and fees since 1979 are presented according to the foregoing categories. The report includes the following data implications: (1) Greater diversity in types of private schools attended occurs as the proportion of enrollment in Catholic schools descreases and the proportion in other religiously affiliated schools increases. (2) Diversity in racial/ethnic background presents mixed trends; fewer black students but about the same number of Hispanics attended private schools in 1985 as in 1979. (3) Relative sizes of private and public school sectors have changed little in recent years. (4) Private schools' tuitions increased considerably faster than the cost of living between 1979-85, especially for church-related schools. Appendices provide statistical methodologies, reliability, standard errors, and references. (CJH)