| 年度 | 实际值 |
|---|---|
| 1992 | 48.6 |
| 1993 | |
| 1994 | |
| 1995 | 49.5 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 51.1 |
| 2000 | 51.8 |
| 2001 | 51.8404 |
| 2002 | 52.0435 |
| 2003 | 52.4435 |
| 2004 | 52.7745 |
| 2005 | 53.095 |
| 2006 | 53.2085 |
| 2007 | 53.4461 |
| 2008 | 53.5672 |
| 2009 | 53.6674 |
| 2010 | 55 |
| 2011 | 55 |
| 2012 | 55 |
| 2013 | 55 |
| 2014 | 56 |
| 2015 | 57 |
| 2016 | 58 |
| 2017 | 57 |