| Value | Category | Cases | |
|---|---|---|---|
| 2017 | 5 |
0.5%
|
|
| 2018 | 43 |
3.9%
|
|
| 2019 | 50 |
4.6%
|
|
| 9999 | NO RESPONSE | 2 |
0.2%
|
| Sysmiss | 996 |
90.9%
|