| 年度 | 实际值 |
|---|---|
| 1992 | 6.8 |
| 1993 | 6.2 |
| 1994 | |
| 1995 | 7 |
| 1996 | 7.55 |
| 1997 | 7.39 |
| 1998 | 3.71 |
| 1999 | 5.79 |
| 2000 | 11.14 |
| 2001 | 5.04 |
| 2002 | 5 |
| 2003 | 5.66 |
| 2004 | 6.47 |
| 2005 | 7.16 |
| 2006 | 6.64 |
| 2007 | 7.35 |
| 2008 | 5.41 |
| 2009 | |
| 2010 | 5.22 |
| 2011 | 7.8 |
| 2012 | 3.9 |
| 2013 | 10.6 |
| 2014 | 8.9 |
| 2015 | 7.82 |
| 2016 | 9.9 |
| 2017 | -0.42 |
| 2018 | 6.38 |