| Value | Category | Cases | |
|---|---|---|---|
| 1 | None | 7 |
5.2%
|
| 2 | 1 or 2 books | 6 |
4.4%
|
| 3 | 3 to 9 books | 34 |
25.2%
|
| 4 | 10 or more books | 88 |
65.2%
|
| Sysmiss | 755 |