| 年度 | 实际值 |
|---|---|
| 1992 | 67.2 |
| 1993 | |
| 1994 | |
| 1995 | 67 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 68.4 |
| 2000 | 68.4 |
| 2001 | 68.3 |
| 2002 | 68 |
| 2003 | 67.8 |
| 2004 | 67.8 |
| 2005 | 67.8 |
| 2006 | 67.9 |
| 2007 | 68.06 |
| 2008 | 57.9 |
| 2009 | 58.1 |
| 2010 | 58.1 |
| 2011 | 58.2 |
| 2012 | 58.3 |
| 2013 | 58.3 |
| 2014 | 58.4 |
| 2015 | 58.5 |
| 2016 | 58.6394 |
| 2017 | 58.8 |
| 2018 | 58.6788 |