Value |
Category |
-9 |
don't know (spontaneous) |
1973 |
|
1974 |
|
1987 |
|
1989 |
|
1990 |
|
1995 |
|
1996 |
|
1998 |
|
1999 |
|
2001 |
|
2004 |
|
2009 |
|
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.