| 年度 | 实际值 |
|---|---|
| 1992 | 8.2 |
| 1993 | |
| 1994 | |
| 1995 | 8.4 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 8.7 |
| 2000 | 8.7086 |
| 2001 | 8.7472 |
| 2002 | 8.7617 |
| 2003 | 8.8427 |
| 2004 | 8.7415 |
| 2005 | 9.09 |
| 2006 | 8.9 |
| 2007 | 8.81 |
| 2008 | 8.806 |
| 2009 | 8.8363 |
| 2010 | 8.8183 |
| 2011 | 8.821 |
| 2012 | 8.8388 |
| 2013 | 8.866 |
| 2014 | 9.16 |
| 2015 | 9.18679748428946 |
| 2016 | 9 |
| 2017 | 9 |