| 年度 | 实际值 |
|---|---|
| 1995 | 45.4 |
| 1996 | 44.5 |
| 1997 | 45.66 |
| 1998 | 44.8 |
| 1999 | 47.8 |
| 2000 | 29.1 |
| 2001 | 50.6 |
| 2002 | 51.51 |
| 2003 | 48.41 |
| 2004 | 46.64 |
| 2005 | 42.26 |
| 2006 | 37.84 |
| 2007 | 42.03 |
| 2008 | 37.57 |
| 2009 | |
| 2010 | 42.42 |
| 2011 | 37.14 |
| 2012 | 30.47 |
| 2013 | 29 |
| 2014 | 28.54 |
| 2015 | 30.15 |
| 2016 | 29.84 |
| 2017 | 27.8 |
| 2018 | 33.14 |