| 年度 | 实际值 |
|---|---|
| 1993 | 37.4 |
| 1994 | |
| 1995 | 37.1 |
| 1996 | 40.8 |
| 1997 | 37.4 |
| 1998 | 37.9 |
| 1999 | 38 |
| 2000 | 38.1 |
| 2001 | 2.58666666666667 |
| 2002 | |
| 2003 | 39 |
| 2004 | 38.94 |
| 2005 | 41 |
| 2006 | 41.54 |
| 2007 | 40.24 |
| 2008 | 37.88 |
| 2009 | |
| 2010 | 36.14 |
| 2011 | 36.35 |
| 2012 | 35.07 |
| 2013 | 27.18 |
| 2014 | 38.82 |
| 2015 | 38.78 |
| 2016 | 38.53 |
| 2017 | 41.36 |
| 2018 | 41.58 |