- 1908 to 19092,639
- 1910 to 19112,820
- 1912 to 19143,299
- 1915 to 19162,938
- 1917 to 19197,077
- 1920 to 19213,646
- 1922 to 19245,403
- 1925 to 19263,839
- 1927 to 19294,071
- 1930 to 19313,033
- 19321,919
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