Value | Category |
---|---|
1 | Daily |
2 | 3-4 times a week |
3 | 3-4 times a month |
4 | 3-4 times a year |
5 | Once a year |
6 | Twice a year |
8 | One time (only once) |
9 | Once per 2 years |
13 | Once per two months |
14 | Once per 3 months |
15 | It was a first trip |
99 | DK/NR |
Sysmiss |