| All Duke Libraries Supplementary Statistics |
| Volume and Title Count Metrics |
| Number of electronic books held | 601,882 |
| Electronic Books |
| Expenditures for ebooks | $658,103 |
| Services |
| Virtual Reference Transactions (ARL only) | 33,798 |
| Use of Networked Electronic Resources |
| ARL S6 Number of sessions (logins) to databases or services | 381,622 |
| ARL S6a Number of resources for which you are reporting | 220 |
| ARL S7 Number of searches (queries) in databases or services | 1,604,034 |
| ARL S7a Number of resources for which you are reporting | 12 |
| Number of successful full-text article requests | 207,213 |
| ARL S8a Number of resources for which you are reporting | 426 |
| ARL S9a Number of virtual visits to library's website | 9,413,821 |
| ARL S9b Number of virtual visits to library's catalog | 1,015,522 |
| Total Number of Virtual Visits (9a + 9b) | 10,429,343 |
| Number and Size of Library Digital Collections |
| S10a. Number of Collections | 197 |
| S10b. Size (in gigabytes) | 546,012.40 |
| S10c. Items | 203,401 |
| Use of Library Digital Collections |
| S11a. Number of times items accessed | 5,000,900 |
| S11b. Number of queries conducted | 267,348 |
| Direct cost of digital collections construction and management |
| S12a. Direct cost of personnel | $111,360 |
| S12b. Direct cost of equipment, software or contracted services | $264,491 |
| Volumes Held Collectively |