| Value | Category | Cases | |
|---|---|---|---|
| 1 | None | 22 |
3.1%
|
| 2 | 1 or 2 books | 46 |
6.4%
|
| 3 | 3 to 9 books | 193 |
26.8%
|
| 4 | 10 or more books | 458 |
63.7%
|
| Sysmiss | 171 |