| 年度 | 实际值 |
|---|---|
| 1992 | 73.4 |
| 1993 | |
| 1994 | |
| 1995 | 73.8 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 73.8 |
| 2000 | 73.99 |
| 2001 | 73.86 |
| 2002 | 73.73 |
| 2003 | 73.54 |
| 2004 | 73.47 |
| 2005 | 73.38 |
| 2006 | 73.39 |
| 2007 | 73.37 |
| 2008 | 73.42 |
| 2009 | 73.37 |
| 2010 | 73.43 |
| 2011 | 73.46 |
| 2012 | 73.46 |
| 2013 | 73.37 |
| 2014 | 73.31 |
| 2015 | 73.05 |
| 2016 | 72.9887 |
| 2017 | 72.9 |
| 2018 | 72.6304 |