| 年度 | 实际值 |
|---|---|
| 1995 | 65.9 |
| 1996 | 64.5 |
| 1997 | 64.11 |
| 1998 | 59.6 |
| 1999 | 58.4 |
| 2000 | 59.8 |
| 2001 | 60.05 |
| 2002 | 59.26 |
| 2003 | 58.54 |
| 2004 | 60.36 |
| 2005 | 54.31 |
| 2006 | 55.58 |
| 2007 | 55.95 |
| 2008 | 56.76 |
| 2009 | |
| 2010 | 58.7 |
| 2011 | 60.49 |
| 2012 | 59.59 |
| 2013 | 59.29 |
| 2014 | 54.29 |
| 2015 | 48.87 |
| 2016 | 50.38 |
| 2017 | |
| 2018 | 54.82 |