| 年度 | 实际值 |
|---|---|
| 1995 | 52 |
| 1996 | 55.3 |
| 1997 | 56.18 |
| 1998 | 56.6 |
| 1999 | 56.5 |
| 2000 | 56.5 |
| 2001 | 53.86 |
| 2002 | 54.09 |
| 2003 | 53.34 |
| 2004 | 54.8 |
| 2005 | 54.83 |
| 2006 | 57.18 |
| 2007 | 57.26 |
| 2008 | 57.35 |
| 2009 | |
| 2010 | 54.93 |
| 2011 | 53.79 |
| 2012 | 53.26 |
| 2013 | 52.86 |
| 2014 | 51.08 |
| 2015 | 49.26 |
| 2016 | 48.13 |
| 2017 | |
| 2018 | 46.84 |