| Value |
Category |
| 1 |
month and year |
| 2 |
month and age |
| 3 |
year and age |
| 4 |
year |
| 6 |
age |
| 7 |
month |
| 8 |
none |
| 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.