| 年度 | 实际值 |
|---|---|
| 1992 | 7.2 |
| 1993 | |
| 1994 | |
| 1995 | 7.2 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 7.3204 |
| 2000 | 7.0421 |
| 2001 | 7.0381 |
| 2002 | 7.0833 |
| 2003 | 7.135 |
| 2004 | 7.1602 |
| 2005 | 7.0374 |
| 2006 | 7.1293 |
| 2007 | 7.2087 |
| 2008 | 7.2729 |
| 2009 | 7.2827 |
| 2010 | 7.2735 |
| 2011 | 7.3635 |
| 2012 | 7.4099 |
| 2013 | 7.4659 |
| 2014 | 7.2892 |
| 2015 | 7.2277 |
| 2016 | 7 |
| 2017 | 7 |