| 年度 | 实际值 |
|---|---|
| 1995 | 44.2 |
| 1996 | 45.1 |
| 1997 | 51.09 |
| 1998 | 45.2 |
| 1999 | 45.8 |
| 2000 | 43.1 |
| 2001 | 42.35 |
| 2002 | 44.85 |
| 2003 | 43.78 |
| 2004 | 43.54 |
| 2005 | 37.25 |
| 2006 | 37.25 |
| 2007 | 37.35 |
| 2008 | 37.2 |
| 2009 | |
| 2010 | 38.53 |
| 2011 | 43.37 |
| 2012 | 43.91 |
| 2013 | 42.45 |
| 2014 | 42.26 |
| 2015 | 41.39 |
| 2016 | 40.84 |
| 2017 | 42.7 |
| 2018 | 42.23 |