| 年度 | 实际值 |
|---|---|
| 1995 | 50.9 |
| 1996 | 50.8 |
| 1997 | 51.69 |
| 1998 | 53.5 |
| 1999 | 53.8 |
| 2000 | 52 |
| 2001 | 52.93 |
| 2002 | 51.34 |
| 2003 | 51.87 |
| 2004 | 52.23 |
| 2005 | 47.37 |
| 2006 | 50.25 |
| 2007 | 51.89 |
| 2008 | 54.89 |
| 2009 | |
| 2010 | 58.53 |
| 2011 | 59.04 |
| 2012 | 60.03 |
| 2013 | 59.45 |
| 2014 | 59.3 |
| 2015 | 57.87 |
| 2016 | 54.47 |
| 2017 | |
| 2018 | 52.09 |