- 1863 to 18693,217
- 1870 to 18792,747
- 1880 to 18893,423
- 1890 to 18993,715
- 1900 to 19094,180
- 1910 to 19199,019
- 1920 to 19299,720
- 1930 to 19399,662
- 1940 to 194914,956
- 1950 to 195914,190
- 1960 to 196921,995
- 1970 to 197913,767
- 1980 to 198914,121
- 1990 to 19998,250
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