- 1900 to 19091,744
- 1910 to 19195,323
- 1920 to 19294,827
- 1930 to 19394,917
- 1940 to 19495,516
- 1950 to 19593,773
- 1960 to 19698,249
- 1970 to 19793,673
- 1980 to 19896,245
- 1990 to 19951,307
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