| Value |
Category |
| 1 |
monthly |
| 2 |
every two months |
| 3 |
every three months |
| 4 |
every six months |
| 5 |
yearly |
| 6 |
other |
| 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.