- 1962 to 196412,587
- 1965 to 196915,929
- 1970 to 197410,032
- 1975 to 19799,668
- 1980 to 19846,809
- 1985 to 19898,671
- 1990 to 19911,947
The preservation of the Duke University Libraries Digital Collections and the Duke Digital Repository programs are supported in part by the Lowell and Eileen Aptman Digital Preservation Fund