| Year | |
|---|---|
| 1991 | 0.0 |
| 1992 | 0.0 |
| 1993 | 0.0 |
| 1994 | 0.0 |
| 1995 | 0.0 |
| 1996 | 0.0 |
| 1997 | 0.0 |
| 1998 | 0.0 |
| 1999 | 90.4 |
| 2000 | 62.8 |
| 2001 | 101.2 |
| 2002 | 157.3 |
| 2003 | 113.8 |
| 2004 | 122.3 |
| 2005 | 116.5 |
| 2006 | 102.6 |
| 2007 | 121.6 |
| 2008 | 149.4 |
| 2009 | 234.9 |
| 2010 | 293.7 |
| 2011 | 233.6 |
| 2012 | 191.6 |
| 2013 | 245.2 |
| 2014 | 216.8 |