| Value | Category | Cases | |
|---|---|---|---|
| 1981 | 1 |
0.3%
|
|
| 1990 | 4 |
1.1%
|
|
| 1991 | 1 |
0.3%
|
|
| 1992 | 3 |
0.8%
|
|
| 1993 | 5 |
1.4%
|
|
| 1995 | 2 |
0.5%
|
|
| 1999 | 1 |
0.3%
|
|
| 2001 | 1 |
0.3%
|
|
| 2002 | 64 |
17.4%
|
|
| 2003 | 98 |
26.7%
|
|
| 2004 | 14 |
3.8%
|
|
| 2005 | 6 |
1.6%
|
|
| 2007 | 5 |
1.4%
|
|
| 2009 | 1 |
0.3%
|
|
| 2010 | 2 |
0.5%
|
|
| 2011 | 79 |
21.5%
|
|
| 2012 | 2 |
0.5%
|
|
| 2013 | 1 |
0.3%
|
|
| Missing value | 77 |
21%
|