| 年度 | 实际值 |
|---|---|
| 1992 | 47.6 |
| 1993 | |
| 1994 | |
| 1995 | 48.3 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 51.8 |
| 2000 | 52.1 |
| 2001 | 52.287 |
| 2002 | 52.4998 |
| 2003 | 52.6992 |
| 2004 | 52.9503 |
| 2005 | 53.3152 |
| 2006 | 53.6314 |
| 2007 | 53.6358 |
| 2008 | 53.9241 |
| 2009 | 54.2386 |
| 2010 | 54 |
| 2011 | 54 |
| 2012 | 53 |
| 2013 | 54 |
| 2014 | 54 |
| 2015 | 55 |
| 2016 | 56 |
| 2017 | 57 |