| 年度 | 实际值 |
|---|---|
| 1992 | 7.7 |
| 1993 | 10.6 |
| 1994 | |
| 1995 | 12.36 |
| 1996 | 12.45 |
| 1997 | 8.37 |
| 1998 | 4.72 |
| 1999 | 8.5 |
| 2000 | 14.14 |
| 2001 | 4.73 |
| 2002 | 4.66 |
| 2003 | 5.19 |
| 2004 | 3.86 |
| 2005 | 5.48 |
| 2006 | 5.99 |
| 2007 | 6.5 |
| 2008 | 11.07 |
| 2009 | |
| 2010 | 14.5 |
| 2011 | 7.2 |
| 2012 | 8.2 |
| 2013 | 13.9 |
| 2014 | 13 |
| 2015 | 10.7 |
| 2016 | 10.69 |
| 2017 | 5.83 |
| 2018 | 9.84 |