| Year | Count |
|---|---|
| 1973 | 10 |
| 1974 | 6 |
| 1975 | 19 |
| 1976 | 25 |
| 1977 | 10 |
| 1978 | 6 |
| 1979 | 26 |
| 1980 | 35 |
| 1981 | 7 |
| 1982 | 40 |
| 1983 | 5 |
| 1984 | 23 |
| 1985 | 27 |
| 1986 | 6 |
| 1987 | 26 |
| 1988 | 11 |
| 1989 | 7 |
| 1990 | 6 |
| 1995 | 10 |
| 1997 | 7 |
| 1998 | 6 |
| 1999 | 22 |
| 2001 | 19 |
| 2003 | 17 |
| 2004 | 5 |
| 2006 | 6 |
| 2008 | 14 |
| 2009 | 5 |
| 2011 | 5 |
| 2013 | 10 |
| 2014 | 5 |
| 2016 | 22 |
| 2017 | 14 |