- 1963 to 196411,457
- 1965 to 196915,850
- 1970 to 19749,898
- 1975 to 19799,590
- 1980 to 19846,803
- 1985 to 19898,662
- 1990 to 19945,126
- 19952,244
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