| 年度 | 实际值 |
|---|---|
| 1995 | 77.6 |
| 1996 | 75.7 |
| 1997 | 73.84 |
| 1998 | 75.4 |
| 1999 | 75 |
| 2000 | 76.4 |
| 2001 | 76.3 |
| 2002 | 76.46 |
| 2003 | 77.21 |
| 2004 | 68.27 |
| 2005 | 68.65 |
| 2006 | 66.69 |
| 2007 | 66.77 |
| 2008 | 64.94 |
| 2009 | |
| 2010 | 61.76 |
| 2011 | 55.32 |
| 2012 | 53.69 |
| 2013 | 53.43 |
| 2014 | 51.83 |
| 2015 | 49.22 |
| 2016 | 45.72 |
| 2017 | 43.22 |
| 2018 | 41.19 |