- 1905 to 19093,377
- 1910 to 19199,501
- 1920 to 192910,348
- 1930 to 193910,889
- 1940 to 194916,350
- 1950 to 195915,194
- 1960 to 196922,880
- 1970 to 197914,459
- 1980 to 198914,481
- 1990 to 199910,792
- 20001,240
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