| 年度 | 实际值 |
|---|---|
| 1992 | 6.4 |
| 1993 | 8.4 |
| 1994 | |
| 1995 | 10.6 |
| 1996 | 4.35 |
| 1997 | |
| 1998 | |
| 1999 | |
| 2000 | 9.48 |
| 2001 | 7.72 |
| 2002 | 9.67 |
| 2003 | 9.97 |
| 2004 | 11.57 |
| 2005 | 10.48 |
| 2006 | 15.09 |
| 2007 | 13.36 |
| 2008 | 12.14 |
| 2009 | |
| 2010 | 7.47 |
| 2011 | 12.2 |
| 2012 | 6.9 |
| 2013 | 9.6 |
| 2014 | 37.4 |
| 2015 | 10.35 |
| 2016 | 6.96 |
| 2017 | 5.67 |
| 2018 | 10.18 |