| 年度 | 实际值 |
|---|---|
| 1992 | 7.6 |
| 1993 | 7 |
| 1994 | |
| 1995 | 9.74 |
| 1996 | 9.57 |
| 1997 | 9.56 |
| 1998 | 4.61 |
| 1999 | 10.25 |
| 2000 | 15.86 |
| 2001 | 10 |
| 2002 | 10.82 |
| 2003 | 11.38 |
| 2004 | 17.72 |
| 2005 | 13 |
| 2006 | 15.97 |
| 2007 | 15.31 |
| 2008 | 19.59 |
| 2009 | |
| 2010 | 40.78 |
| 2011 | 7.3 |
| 2012 | 6.9 |
| 2013 | 19.2 |
| 2014 | 4.3 |
| 2015 | 15.87 |
| 2016 | 13.78 |
| 2017 | 5.69 |
| 2018 | 14.16 |