- 1970 to 19717,716
- 1972 to 19736,904
- 1974 to 19756,635
- 1976 to 19776,631
- 1978 to 19797,675
- 1980 to 19813,541
- 1982 to 19833,464
- 1984 to 19854,620
- 1986 to 19874,708
- 1988 to 19892,510
- 1990 to 19911,943
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