- 1930 to 19399,677
- 1940 to 194914,981
- 1950 to 195914,230
- 1960 to 196922,030
- 1970 to 197913,796
- 1980 to 198914,141
- 1990 to 19998,270
- 2000 to 20092,258
- 2010 to 20131,028
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