| 年度 | 实际值 |
|---|---|
| 1992 | 6.8 |
| 1993 | |
| 1994 | |
| 1995 | 6.7 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 6.8169 |
| 2000 | 6.7834 |
| 2001 | 6.8022 |
| 2002 | 6.885 |
| 2003 | 6.7907 |
| 2004 | 6.8438 |
| 2005 | 6.8402 |
| 2006 | 6.8773 |
| 2007 | 6.9163 |
| 2008 | 6.9287 |
| 2009 | 6.9198 |
| 2010 | 6.8943 |
| 2011 | 6.9132 |
| 2012 | 6.9233 |
| 2013 | 6.9435 |
| 2014 | 6.9006 |
| 2015 | 6.8337 |
| 2016 | 7 |
| 2017 | 7 |