| Value | Category | Cases | |
|---|---|---|---|
| 2015 | 173 |
4.9%
|
|
| 2016 | 516 |
14.5%
|
|
| 2017 | 555 |
15.6%
|
|
| 2018 | 222 |
6.2%
|
|
| 9997 | 7 |
0.2%
|
|
| 9999 | NO RESPONSE | 18 |
0.5%
|
| Sysmiss | 2069 |
58.1%
|