| Value | Category | Cases | |
|---|---|---|---|
| 1 | textbook | 19 |
82.6%
|
| 2 | multimedia | 1 |
4.3%
|
| 3 | workbook | 1 |
4.3%
|
| 4 | 2 |
8.7%
|
|
| Sysmiss | 27 |