| 年度 | 实际值 |
|---|---|
| 1995 | 57.2 |
| 1996 | 65.2 |
| 1997 | 53.32 |
| 1998 | 53.4 |
| 1999 | 52.8 |
| 2000 | 55.3 |
| 2001 | 52.37 |
| 2002 | 54.09 |
| 2003 | 54.6 |
| 2004 | 56.6 |
| 2005 | 61.51 |
| 2006 | 61.52 |
| 2007 | 57.44 |
| 2008 | 60.38 |
| 2009 | |
| 2010 | 57.98 |
| 2011 | 56.22 |
| 2012 | 54.85 |
| 2013 | 53.89 |
| 2014 | 51.42 |
| 2015 | 49.27 |
| 2016 | 49.26 |
| 2017 | 49.7 |
| 2018 | 50.1 |