| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 5 |
0.4%
|
| 1 | By Parliament | 336 |
28%
|
| 2 | By a public referendum | 598 |
49.8%
|
| 3 | By some other method | 74 |
6.2%
|
| 9 | Don't know | 187 |
15.6%
|