| 年度 | 实际值 |
|---|---|
| 1993 | 6.7 |
| 1994 | |
| 1995 | 7.53 |
| 1996 | 8.1 |
| 1997 | 8.36 |
| 1998 | 4.03 |
| 1999 | 6.43 |
| 2000 | 12.07 |
| 2001 | 6.36 |
| 2002 | 8.3 |
| 2003 | 9.34 |
| 2004 | 17.85 |
| 2005 | 10.02 |
| 2006 | 17.4 |
| 2007 | 19.11 |
| 2008 | 18.33 |
| 2009 | |
| 2010 | 21.84 |
| 2011 | 5.3 |
| 2012 | 12.9 |
| 2013 | 18.1 |
| 2014 | 19.4 |
| 2015 | 17.36 |
| 2016 | 15 |
| 2017 | 6.1 |
| 2018 | 15.34 |