- 1827 to 18391,232
- 1840 to 18593,388
- 1860 to 18797,413
- 1880 to 18997,851
- 1900 to 191912,909
- 1920 to 193921,152
- 1940 to 195930,277
- 1960 to 197935,387
- 1980 to 199116,089
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