Data for this should be in Adult Female Offenders and Institutional Programs - A State of the Art Analysis, a 1984 report from the University of South Carolina which "analyzes the population of adult female offenders, as well as the programs and services available to them," with comparative data back to 1975.

The abstract states that "the age and prior education of adult female offenders has not changed significantly." Presumably the full report would have the numbers to back up that claim.

The report is not widely held - it is on microfiche, only in 16 libraries.