| 年度 | 实际值 |
|---|---|
| 1995 | 44.9 |
| 1996 | 43.8 |
| 1997 | 41.26 |
| 1998 | 42.8 |
| 1999 | 42.4 |
| 2000 | 38.6 |
| 2001 | 39.37 |
| 2002 | 40 |
| 2003 | 38.25 |
| 2004 | 41.06 |
| 2005 | 33.13 |
| 2006 | 33.38 |
| 2007 | 33.91 |
| 2008 | 44.04 |
| 2009 | |
| 2010 | 40.75 |
| 2011 | 46.46 |
| 2012 | 46.56 |
| 2013 | 45.73 |
| 2014 | 44.09 |
| 2015 | 42.2 |
| 2016 | 38.42 |
| 2017 | 35.39 |
| 2018 | 32.86 |