| 年度 | 实际值 |
|---|---|
| 1993 | 29.6 |
| 1994 | |
| 1995 | 20.4 |
| 1996 | 20.7 |
| 1997 | 22.6 |
| 1998 | 24.6 |
| 1999 | 26.5 |
| 2000 | 27.4 |
| 2001 | 1.86666666666667 |
| 2002 | |
| 2003 | 24.46 |
| 2004 | 23.48 |
| 2005 | 25 |
| 2006 | 25.96 |
| 2007 | 42.46 |
| 2008 | 42.72 |
| 2009 | |
| 2010 | 44.17 |
| 2011 | 43.47 |
| 2012 | 43.47 |
| 2013 | 43.47 |
| 2014 | 46.5 |
| 2015 | 42.73 |
| 2016 | 45.49 |
| 2017 | 39.85 |
| 2018 | 39.85 |