| 年度 | 实际值 |
|---|---|
| 1995 | 79.5 |
| 1996 | 71 |
| 1997 | 21.74 |
| 1998 | 71.3 |
| 1999 | 68.4 |
| 2000 | 68 |
| 2001 | 66.2 |
| 2002 | 66.52 |
| 2003 | 66.91 |
| 2004 | 67.26 |
| 2005 | 64.09 |
| 2006 | 67.76 |
| 2007 | 68.95 |
| 2008 | 69.4 |
| 2009 | |
| 2010 | 66.76 |
| 2011 | 68 |
| 2012 | 67.85 |
| 2013 | 65.53 |
| 2014 | 62.03 |
| 2015 | 57.02 |
| 2016 | 51.17 |
| 2017 | 49.89 |
| 2018 | 53.36 |