| 年度 | 实际值 |
|---|---|
| 1992 | 86.2 |
| 1993 | 85.8 |
| 1994 | 85.43 |
| 1995 | 85.6 |
| 1996 | 85.89 |
| 1997 | 85.44 |
| 1998 | 84.82 |
| 1999 | 84.45 |
| 2000 | 84.9 |
| 2001 | 84.56 |
| 2002 | 84.31 |
| 2003 | 83.74 |
| 2004 | 82.87 |
| 2005 | 82.13 |
| 2006 | 81.62 |
| 2007 | 81.26 |
| 2008 | 81.08 |
| 2009 | |
| 2010 | 81.03 |
| 2011 | 80.3 |
| 2012 | 80.6 |
| 2013 | 78.9 |
| 2014 | 78 |
| 2015 | 76.89 |
| 2016 | 75 |
| 2017 | 74 |
| 2018 | 73 |