| Year | Count |
|---|---|
| 1983 | 5 |
| 1986 | 22 |
| 1987 | 24 |
| 1988 | 51 |
| 1989 | 40 |
| 1990 | 46 |
| 1991 | 30 |
| 1992 | 125 |
| 1993 | 196 |
| 1994 | 267 |
| 1995 | 402 |
| 1996 | 401 |
| 1997 | 397 |
| 1998 | 522 |
| 1999 | 470 |
| 2000 | 449 |
| 2001 | 464 |
| 2002 | 283 |
| 2003 | 215 |
| 2004 | 340 |
| 2005 | 292 |
| 2006 | 262 |
| 2007 | 276 |
| 2008 | 433 |
| 2009 | 270 |
| 2010 | 124 |
| 2011 | 119 |
| 2012 | 68 |
| 2014 | 14 |
| 2015 | 43 |
| 2016 | 6 |
| 2017 | 5 |
| 2018 | 5 |