| 年度 | 实际值 |
|---|---|
| 1992 | 64.8 |
| 1993 | |
| 1994 | |
| 1995 | 66 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 67 |
| 2000 | 67.09 |
| 2001 | 67.2 |
| 2002 | 67.31 |
| 2003 | 67.39 |
| 2004 | 65.86 |
| 2005 | 65.65 |
| 2006 | 65.72 |
| 2007 | 65.94 |
| 2008 | 66.15 |
| 2009 | 66.28 |
| 2010 | 66.36 |
| 2011 | 66.24 |
| 2012 | 65.59 |
| 2013 | 65.13 |
| 2014 | 64.3 |
| 2015 | 63.84 |
| 2016 | 62.8 |
| 2017 | 61 |
| 2018 | 60.7753 |