| 年度 | 实际值 |
|---|---|
| 1992 | 71.1 |
| 1993 | |
| 1994 | |
| 1995 | 70.2 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 69.5 |
| 2000 | 69 |
| 2001 | 68.5 |
| 2002 | 68 |
| 2003 | 67.4 |
| 2004 | 66.9 |
| 2005 | 66.6 |
| 2006 | 66.6 |
| 2007 | 66.65 |
| 2008 | 66.7 |
| 2009 | 66.7 |
| 2010 | 66.4 |
| 2011 | 66.5 |
| 2012 | 66 |
| 2013 | 66 |
| 2014 | 65.86 |
| 2015 | 65.51 |
| 2016 | 65.4062 |
| 2017 | 64.5 |
| 2018 | 64.2643 |