| 年度 | 实际值 |
|---|---|
| 1995 | 56.8 |
| 1996 | 56.4 |
| 1997 | 57.73 |
| 1998 | 55.5 |
| 1999 | 52.5 |
| 2000 | 54.7 |
| 2001 | 52.36 |
| 2002 | 52.47 |
| 2003 | 56.64 |
| 2004 | 55.4 |
| 2005 | 56.23 |
| 2006 | 50.42 |
| 2007 | 48.93 |
| 2008 | 54.63 |
| 2009 | |
| 2010 | 46.48 |
| 2011 | 54.63 |
| 2012 | 51.43 |
| 2013 | 50.7 |
| 2014 | 50.01 |
| 2015 | 46.43 |
| 2016 | 47.72 |
| 2017 | 50.01 |
| 2018 | 51.15 |