| Year | Count |
|---|---|
| 1976 | 34 |
| 1977 | 63 |
| 1978 | 92 |
| 1979 | 114 |
| 1980 | 150 |
| 1981 | 266 |
| 1982 | 433 |
| 1983 | 406 |
| 1984 | 360 |
| 1985 | 417 |
| 1986 | 366 |
| 1987 | 366 |
| 1988 | 336 |
| 1989 | 299 |
| 1990 | 296 |
| 1991 | 255 |
| 1992 | 250 |
| 1993 | 205 |
| 1994 | 195 |
| 1995 | 111 |
| 1996 | 101 |
| 1997 | 123 |
| 1998 | 80 |
| 1999 | 67 |
| 2000 | 72 |
| 2001 | 34 |
| 2002 | 22 |
| 2003 | 19 |
| 2004 | 45 |
| 2005 | 40 |
| 2006 | 5 |
| 2008 | 5 |
| 2012 | 5 |