| Value | Category | Cases | |
|---|---|---|---|
| 2015 | 18 |
0.5%
|
|
| 2016 | 65 |
1.8%
|
|
| 2017 | 78 |
2.2%
|
|
| 2018 | 133 |
3.7%
|
|
| 9997 | 7 |
0.2%
|
|
| 9999 | NO RESPONSE | 18 |
0.5%
|
| Sysmiss | 3241 |
91%
|