| 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 | 317.8 |
| 2000 | 617.4 |
| 2001 | 1,104.6 |
| 2002 | 891.7 |
| 2003 | 564.5 |
| 2004 | 795.9 |
| 2005 | 1,010.2 |
| 2006 | 1,428.9 |
| 2007 | 1,311.1 |
| 2008 | 1,160.9 |
| 2009 | 615.3 |
| 2010 | 711.5 |
| 2011 | 573.2 |
| 2012 | 735.0 |
| 2013 | 950.3 |
| 2014 | 934.3 |