| 年度 | 实际值 |
|---|---|
| 1995 | 41.8 |
| 1996 | 41.7 |
| 1997 | 46.65 |
| 1998 | 41.2 |
| 1999 | 43 |
| 2000 | 42.3 |
| 2001 | 44.78 |
| 2002 | 43.54 |
| 2003 | 45.44 |
| 2004 | 48.65 |
| 2005 | 44.72 |
| 2006 | 44.37 |
| 2007 | 44.91 |
| 2008 | 43.97 |
| 2009 | |
| 2010 | 42.96 |
| 2011 | 44.2 |
| 2012 | 42.89 |
| 2013 | 42.13 |
| 2014 | 42.66 |
| 2015 | 40.01 |
| 2016 | 37.32 |
| 2017 | |
| 2018 | 33.74 |