| Value | Category | Cases | |
|---|---|---|---|
| -9 | NIU (not in universe) | 2160 |
76.5%
|
| 1 | easy to use method | 296 |
10.5%
|
| 2 | hard to use method | 148 |
5.2%
|
| 98 | don't know | 15 |
0.5%
|
| 9999995 | missing:impute | 203 |
7.2%
|