| 年度 | 实际值 |
|---|---|
| 1992 | 37.72 |
| 1993 | 38.9 |
| 1994 | 41.33 |
| 1995 | 42.73 |
| 1996 | 43.36 |
| 1997 | 43.92 |
| 1998 | 44.52 |
| 1999 | 45.1 |
| 2000 | 45.8 |
| 2001 | 46.02 |
| 2002 | 46.87 |
| 2003 | 46.97 |
| 2004 | 47.27 |
| 2005 | 47.53 |
| 2006 | 47.88 |
| 2007 | 48.6 |
| 2008 | 49.39 |
| 2009 | |
| 2010 | 49.66 |
| 2011 | 50.2 |
| 2012 | 49.2 |
| 2013 | 48.9 |
| 2014 | 49.2 |
| 2015 | 49.44 |
| 2016 | 50 |
| 2017 | 50 |
| 2018 | 50 |