| 年度 | 实际值 |
|---|---|
| 1995 | 68.1 |
| 1996 | 72.2 |
| 1997 | 55.64 |
| 1998 | 64.8 |
| 1999 | 64.6 |
| 2000 | 65.6 |
| 2001 | 65.42 |
| 2002 | 66.12 |
| 2003 | 66.66 |
| 2004 | 68.25 |
| 2005 | 70.57 |
| 2006 | 69.97 |
| 2007 | 68.49 |
| 2008 | 66.02 |
| 2009 | |
| 2010 | 63.66 |
| 2011 | 60.9 |
| 2012 | 59.82 |
| 2013 | 56.25 |
| 2014 | 54.86 |
| 2015 | 52.27 |
| 2016 | 50.26 |
| 2017 | 50.51 |
| 2018 | 51.67 |