| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| 1980 | 1 |
7.1%
|
|
| 1985 | 1 |
7.1%
|
|
| 1988 | 1 |
7.1%
|
|
| 1999 | 1 |
7.1%
|
|
| 2006 | 1 |
7.1%
|
|
| 2008 | 1 |
7.1%
|
|
| 2013 | 1 |
7.1%
|
|
| 2015 | 3 |
21.4%
|
|
| 2017 | 2 |
14.3%
|
|
| 2018 | 2 |
14.3%
|
|
| Sysmiss | 347 |