| 年度 | 实际值 |
|---|---|
| 1992 | 8.5 |
| 1993 | 10.1 |
| 1994 | |
| 1995 | 5.32 |
| 1996 | 4.66 |
| 1997 | 6.49 |
| 1998 | 4.99 |
| 1999 | 7.88 |
| 2000 | 16.93 |
| 2001 | 7.93 |
| 2002 | 7.01 |
| 2003 | 7.71 |
| 2004 | 11.27 |
| 2005 | 6.53 |
| 2006 | 11.79 |
| 2007 | 7.45 |
| 2008 | 15.16 |
| 2009 | |
| 2010 | 11.65 |
| 2011 | 9.5 |
| 2012 | 8.6 |
| 2013 | 15.1 |
| 2014 | 14.6 |
| 2015 | 11.53 |
| 2016 | 12.31 |
| 2017 | 1.79 |
| 2018 | 8.18 |