- 19594,534
- 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 19943,704
- 1995 to 19995,125
- 2000 to 20042,093
- 2005 to 2009191
- 2010346
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