| 年度 | 实际值 |
|---|---|
| 1995 | 56.8 |
| 1996 | 52.2 |
| 1997 | 49.66 |
| 1998 | 48.4 |
| 1999 | 48.1 |
| 2000 | 46.9 |
| 2001 | 46.01 |
| 2002 | 45.78 |
| 2003 | 47.09 |
| 2004 | 46.34 |
| 2005 | 41.79 |
| 2006 | 36 |
| 2007 | |
| 2008 | 36.24 |
| 2009 | |
| 2010 | 29.32 |
| 2011 | 31.44 |
| 2012 | 25.91 |
| 2013 | 26.02 |
| 2014 | 39.72 |
| 2015 | 37.89 |
| 2016 | 38.79 |
| 2017 | 38.88 |
| 2018 | 35.34 |