| Year | Count |
|---|---|
| 1990 | 44 |
| 1991 | 154 |
| 1992 | 333 |
| 1993 | 799 |
| 1994 | 1,351 |
| 1995 | 1,413 |
| 1996 | 1,990 |
| 1997 | 2,058 |
| 1998 | 2,187 |
| 1999 | 1,539 |
| 2000 | 1,343 |
| 2001 | 1,204 |
| 2002 | 950 |
| 2003 | 929 |
| 2004 | 941 |
| 2005 | 737 |
| 2006 | 695 |
| 2007 | 599 |
| 2008 | 500 |
| 2009 | 302 |
| 2010 | 231 |
| 2011 | 140 |
| 2012 | 142 |
| 2013 | 71 |
| 2014 | 44 |
| 2015 | 30 |
| 2017 | 5 |