| 年度 | 实际值 |
|---|---|
| 1995 | 69.1 |
| 1996 | 68.9 |
| 1997 | 74.39 |
| 1998 | 64.5 |
| 1999 | 61.6 |
| 2000 | 60.8 |
| 2001 | 58.99 |
| 2002 | 53.21 |
| 2003 | 55.35 |
| 2004 | 57.82 |
| 2005 | 60.4 |
| 2006 | 62.92 |
| 2007 | 64.57 |
| 2008 | 65.6 |
| 2009 | |
| 2010 | 63.01 |
| 2011 | 63.62 |
| 2012 | 62.2 |
| 2013 | 61.92 |
| 2014 | 61.84 |
| 2015 | 60.46 |
| 2016 | 59.63 |
| 2017 | 57.72 |
| 2018 | 56.5 |