- 1960 to 196413,430
- 1965 to 196915,459
- 1970 to 19749,572
- 1975 to 19799,280
- 1980 to 19846,605
- 1985 to 19898,449
- 1990 to 19943,703
- 1995 to 19995,125
- 20001,094
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