| Value | Category | Cases | |
|---|---|---|---|
| 1 | Never | 3 |
0.1%
|
| 2 | Once a term | 0 |
0%
|
| 3 | Once a month | 4 |
0.2%
|
| 4 | Once a week | 229 |
11.3%
|
| 5 | Nearly every day | 951 |
47%
|
| 98 | Other | 0 |
0%
|
| 99 | No books | 42 |
2.1%
|
| 999 | 795 |
39.3%
|
|
| Sysmiss | 1303 |