| 年度 | 实际值 |
|---|---|
| 1995 | 33.9 |
| 1996 | 34 |
| 1997 | 33.53 |
| 1998 | 39.4 |
| 1999 | 38.9 |
| 2000 | 40.9 |
| 2001 | 42.46 |
| 2002 | 42.96 |
| 2003 | 42.36 |
| 2004 | 42.56 |
| 2005 | 43.79 |
| 2006 | 43.94 |
| 2007 | 40.51 |
| 2008 | 41.68 |
| 2009 | |
| 2010 | 41.5 |
| 2011 | 41.5 |
| 2012 | 40.95 |
| 2013 | 42.22 |
| 2014 | 42.01 |
| 2015 | 41.26 |
| 2016 | 40.57 |
| 2017 | 43.59 |
| 2018 | 43.7 |