- 1861 to 18642,900
- 1865 to 18692,641
- 1870 to 18741,950
- 1875 to 18791,792
- 1880 to 18841,800
- 1885 to 18892,474
- 1890 to 18943,242
- 18952,424
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