| Value |
Category |
| 1 |
Prior to 1991 |
| 2 |
2. 1991 - 1995 |
| 3 |
3. 1996 - 2000 |
| 4 |
4. 2001 - 2004 |
| 9 |
Missing |
| 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.