| 年度 | 实际值 |
|---|---|
| 1992 | 6.4 |
| 1993 | 5.3 |
| 1994 | |
| 1995 | 10.15 |
| 1996 | 9.08 |
| 1997 | |
| 1998 | |
| 1999 | 9.19 |
| 2000 | 14.91 |
| 2001 | 6.36 |
| 2002 | .53 |
| 2003 | 5.2 |
| 2004 | 8.37 |
| 2005 | 5.69 |
| 2006 | 7.77 |
| 2007 | 8.36 |
| 2008 | 12.71 |
| 2009 | |
| 2010 | 7.69 |
| 2011 | 10.4 |
| 2012 | 7.7 |
| 2013 | 7.6 |
| 2014 | 24.4 |
| 2015 | 8.3 |
| 2016 | 10.31 |
| 2017 | 7.36 |
| 2018 | 10.23 |