- 1872 to 18742,501
- 1875 to 18792,671
- 1880 to 18842,701
- 1885 to 18893,387
- 1890 to 18944,295
- 1895 to 18994,371
- 1900 to 19044,474
- 1905 to 19094,186
- 1910 to 19144,820
- 1915 to 19198,740
- 1920 to 19247,915
- 1925 to 19295,779
- 1930 to 19345,266
- 1935 to 19397,714
- 1940 to 19414,659
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