| 年度 | 实际值 |
|---|---|
| 1995 | 64.7 |
| 1996 | 63.8 |
| 1997 | 68.77 |
| 1998 | 56.5 |
| 1999 | 56.1 |
| 2000 | 50.7 |
| 2001 | 52.5 |
| 2002 | 53.81 |
| 2003 | 54.69 |
| 2004 | 56.32 |
| 2005 | 53.82 |
| 2006 | 54.58 |
| 2007 | 53.91 |
| 2008 | 58.76 |
| 2009 | |
| 2010 | 60.74 |
| 2011 | 63.47 |
| 2012 | 62.33 |
| 2013 | 60.39 |
| 2014 | 54.46 |
| 2015 | 47.98 |
| 2016 | 47.24 |
| 2017 | 45.17 |
| 2018 | 44.62 |