| 年度 | 实际值 |
|---|---|
| 1992 | 6.6 |
| 1993 | 3.9 |
| 1994 | |
| 1995 | 8.83 |
| 1996 | 5.97 |
| 1997 | 6.29 |
| 1998 | 5.25 |
| 1999 | 5.4 |
| 2000 | 7.91 |
| 2001 | 4.66 |
| 2002 | 4.6 |
| 2003 | 4.86 |
| 2004 | 5.79 |
| 2005 | 5.51 |
| 2006 | 6.5 |
| 2007 | 7.91 |
| 2008 | 7.49 |
| 2009 | |
| 2010 | 6.26 |
| 2011 | 0 |
| 2012 | 9.7 |
| 2013 | 16.9 |
| 2014 | 16.9 |
| 2015 | 11.67 |
| 2016 | 17.44 |
| 2017 | 12.66 |
| 2018 | 13.65 |