| 年度 | 实际值 |
|---|---|
| 1993 | 28.4 |
| 1994 | |
| 1995 | 20.3 |
| 1996 | 19.3 |
| 1997 | 26.9 |
| 1998 | 20.6 |
| 1999 | 23.4 |
| 2000 | 20.3 |
| 2001 | 1.46 |
| 2002 | |
| 2003 | 26.88 |
| 2004 | 36.08 |
| 2005 | 36 |
| 2006 | 38.67 |
| 2007 | 38.09 |
| 2008 | 38.55 |
| 2009 | |
| 2010 | 38.83 |
| 2011 | 39.17 |
| 2012 | 39.34 |
| 2013 | 40.16 |
| 2014 | 32.5 |
| 2015 | 39.82 |
| 2016 | 41.41 |
| 2017 | 41.63 |
| 2018 | 41.33 |