- 1850 to 1859 1,966
- 1860 to 1879 6,032
- 1880 to 1899 6,093
- 1900 to 1919 11,230
- 1920 to 1939 17,789
- 1940 to 1959 27,633
- 1960 to 1979 34,120
- 1980 to 1999 21,988
- 2000 to 2009 2,248
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