| 年度 | 实际值 |
|---|---|
| 1992 | 67.52 |
| 1993 | 67.87 |
| 1994 | 68.81 |
| 1995 | 69.39 |
| 1996 | 69.44 |
| 1997 | 69.38 |
| 1998 | 69.54 |
| 1999 | 69.27 |
| 2000 | 69.7 |
| 2001 | 69.6 |
| 2002 | 69.12 |
| 2003 | 68.91 |
| 2004 | 68.37 |
| 2005 | 68.46 |
| 2006 | 68.45 |
| 2007 | 67.94 |
| 2008 | 67.95 |
| 2009 | |
| 2010 | 67.87 |
| 2011 | 67.3 |
| 2012 | 67.3 |
| 2013 | 66.8 |
| 2014 | 66 |
| 2015 | 64.86 |
| 2016 | 64 |
| 2017 | 62 |
| 2018 | 61 |