| Year | Total | vs prev |
|---|---|---|
| 2006 | 0 | −100.0% |
| 2005 | 7 | −96.2% |
| 2004 | 186 | −88.7% |
| 2003 | 1,641 | −36.3% |
| 2002 | 2,576 | −7.1% |
| 2001 | 2,772 | −22.5% |
| 2000 | 3,576 | −16.4% |
| 1999 | 4,275 | +8.4% |
| 1998 | 3,942 | +50.6% |
| 1997 | 2,618 | +98.2% |
| 1996 | 1,321 | +1.1% |
| 1995 | 1,306 | +14.3% |
| 1994 | 1,143 | −38.7% |
| 1993 | 1,864 | −30.4% |
| 1992 | 2,678 | +74.7% |
| 1991 | 1,533 | — |