| 年度 | 实际值 |
|---|---|
| 1995 | 61.4 |
| 1996 | 64.8 |
| 1997 | 65.41 |
| 1998 | 61.3 |
| 1999 | 58.7 |
| 2000 | 57.9 |
| 2001 | 58.11 |
| 2002 | 58.56 |
| 2003 | 60.32 |
| 2004 | 62.02 |
| 2005 | 57.63 |
| 2006 | 59.38 |
| 2007 | 59.07 |
| 2008 | 59.21 |
| 2009 | |
| 2010 | 59.46 |
| 2011 | 59.44 |
| 2012 | 58.89 |
| 2013 | 57.68 |
| 2014 | 54.63 |
| 2015 | 49.83 |
| 2016 | 48.03 |
| 2017 | |
| 2018 | 47.03 |