| 年度 | 实际值 |
|---|---|
| 1992 | 5.9 |
| 1993 | 7.2 |
| 1994 | |
| 1995 | 3.09 |
| 1996 | 4.17 |
| 1997 | 7.17 |
| 1998 | 3.03 |
| 1999 | 9.25 |
| 2000 | 13.12 |
| 2001 | 7.28 |
| 2002 | 8.55 |
| 2003 | 7.68 |
| 2004 | 7.34 |
| 2005 | 3.18 |
| 2006 | 8.05 |
| 2007 | 8.66 |
| 2008 | 9.05 |
| 2009 | |
| 2010 | 8.66 |
| 2011 | 9.5 |
| 2012 | 4.3 |
| 2013 | 4.3 |
| 2014 | 4.7 |
| 2015 | 5.7 |
| 2016 | 5.5 |
| 2017 | 6.21 |
| 2018 | 8.7 |