| Value |
Category |
| 1 |
1 more than once |
| 2 |
2 once |
| 3 |
3 none, but i wanted to participate |
| 4 |
4 none, and i did not want to participate |
| 98 |
don't know |
| Sysmiss |
|
Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.