| Value |
Category |
| -9 |
Don't know (spontaneous) |
| 1968 |
|
| 2001 |
|
| 2002 |
|
| 2007 |
|
| 2008 |
|
| 2009 |
|
| 2010 |
|
| 2011 |
|
| 2014 |
|
| 2016 |
|
| 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.