| 年度 | 实际值 |
|---|---|
| 1995 | 56.8 |
| 1996 | 59.5 |
| 1997 | 61.96 |
| 1998 | 60 |
| 1999 | 50.1 |
| 2000 | 50.6 |
| 2001 | 51.46 |
| 2002 | 52.63 |
| 2003 | 55.47 |
| 2004 | 59.84 |
| 2005 | 61.98 |
| 2006 | 64.19 |
| 2007 | 65.68 |
| 2008 | 66.85 |
| 2009 | |
| 2010 | 68.65 |
| 2011 | 68.89 |
| 2012 | 67.46 |
| 2013 | 67.42 |
| 2014 | 61.8 |
| 2015 | 59.76 |
| 2016 | 59.28 |
| 2017 | |
| 2018 | 56.58 |