| 年度 | 实际值 |
|---|---|
| 1992 | 67.8 |
| 1993 | |
| 1994 | |
| 1995 | 67.4 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 66.5 |
| 2000 | 66 |
| 2001 | 65.4 |
| 2002 | 65 |
| 2003 | 64.2 |
| 2004 | 63.6 |
| 2005 | 63.1 |
| 2006 | 62.8 |
| 2007 | 62.75 |
| 2008 | 62.8 |
| 2009 | 63 |
| 2010 | 62.7 |
| 2011 | 62.6 |
| 2012 | 62.2 |
| 2013 | 58.8 |
| 2014 | 61.77 |
| 2015 | 61.28 |
| 2016 | 60.9765 |
| 2017 | 60.1 |
| 2018 | 59.3738 |