| 年度 | 实际值 |
|---|---|
| 1992 | 11.4 |
| 1993 | 11.9 |
| 1994 | |
| 1995 | 9.56 |
| 1996 | 9.25 |
| 1997 | 7.77 |
| 1998 | 3.6 |
| 1999 | 8.47 |
| 2000 | 12.22 |
| 2001 | 6.94 |
| 2002 | 4.84 |
| 2003 | 5.57 |
| 2004 | 5.79 |
| 2005 | 4.59 |
| 2006 | 4.7 |
| 2007 | 7.92 |
| 2008 | 6.11 |
| 2009 | |
| 2010 | 5.78 |
| 2011 | 4 |
| 2012 | -2 |
| 2013 | 8.2 |
| 2014 | 6.5 |
| 2015 | 10.86 |
| 2016 | 10.67 |
| 2017 | 0.95 |
| 2018 | 9.32 |