| 年度 | 实际值 |
|---|---|
| 1992 | 48.1 |
| 1993 | |
| 1994 | |
| 1995 | 48.4 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 49.1 |
| 2000 | 49.08 |
| 2001 | 48.82 |
| 2002 | 48.44 |
| 2003 | 48.15 |
| 2004 | 47.94 |
| 2005 | 47.88 |
| 2006 | 47.93 |
| 2007 | 48.03 |
| 2008 | 48.16 |
| 2009 | 48.21 |
| 2010 | 48.35 |
| 2011 | 48.39 |
| 2012 | 48.35 |
| 2013 | 48.37 |
| 2014 | 48.37 |
| 2015 | 48.34 |
| 2016 | 48.3761 |
| 2017 | 48 |