| Value | Category | Cases | |
|---|---|---|---|
| 1 | Never | 3 |
0.1%
|
| 2 | Once a term | 3 |
0.1%
|
| 3 | Once a month | 31 |
1.5%
|
| 4 | Once a week | 352 |
17.4%
|
| 5 | Nearly every day | 1195 |
59%
|
| 98 | Other | 0 |
0%
|
| 99 | No books | 15 |
0.7%
|
| 999 | 425 |
21%
|
|
| Sysmiss | 1303 |