Value |
Category |
1 |
2011-2012 |
2 |
2008-2010 |
3 |
2001-2007 |
4 |
2000-2006 |
5 |
1999 and before |
9 |
Missing values |
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.