| Year | Total | vs prev |
|---|---|---|
| 2012 | 3,367 | +1.4% |
| 2011 | 3,320 | −9.2% |
| 2010 | 3,658 | +3.2% |
| 2009 | 3,544 | −13.7% |
| 2008 | 4,108 | +9.3% |
| 2007 | 3,757 | +2.2% |
| 2006 | 3,677 | +9.8% |
| 2005 | 3,350 | +8.1% |
| 2004 | 3,100 | +6.8% |
| 2003 | 2,903 | +4.0% |
| 2002 | 2,792 | +3.8% |
| 2001 | 2,689 | −5.0% |
| 2000 | 2,830 | −10.8% |
| 1999 | 3,171 | +25.9% |
| 1998 | 2,519 | +21.3% |
| 1997 | 2,076 | — |