| 年度 | 实际值 |
|---|---|
| 1995 | 68.4 |
| 1996 | 73 |
| 1997 | 76.8 |
| 1998 | 77.8 |
| 1999 | 77.1 |
| 2000 | 77.3 |
| 2001 | 68.37 |
| 2002 | 65.49 |
| 2003 | 65.47 |
| 2004 | 67.04 |
| 2005 | 67.95 |
| 2006 | 68.22 |
| 2007 | 64.67 |
| 2008 | 64.71 |
| 2009 | |
| 2010 | 62.67 |
| 2011 | 62.94 |
| 2012 | 58.9 |
| 2013 | 53.81 |
| 2014 | 44.26 |
| 2015 | 39.36 |
| 2016 | 39.86 |
| 2017 | 35.77 |
| 2018 | 37.6 |