| 年度 | 实际值 |
|---|---|
| 1993 | 16.9 |
| 1994 | |
| 1995 | 13.6 |
| 1996 | 30.1 |
| 1997 | 37.3 |
| 1998 | 38.8 |
| 1999 | 39.2 |
| 2000 | 35.3 |
| 2001 | 2.42666666666667 |
| 2002 | |
| 2003 | 40.28 |
| 2004 | 34.94 |
| 2005 | 39 |
| 2006 | 40.61 |
| 2007 | 40.72 |
| 2008 | 30.59 |
| 2009 | |
| 2010 | 40.61 |
| 2011 | 40.58 |
| 2012 | 10.93 |
| 2013 | 12.41 |
| 2014 | 34.4 |
| 2015 | 42.71 |
| 2016 | 30.93 |
| 2017 | 48.6 |
| 2018 | 42.02 |