| 年度 | 实际值 |
|---|---|
| 1995 | 64.7 |
| 1996 | 70.5 |
| 1997 | 51.04 |
| 1998 | 74.3 |
| 1999 | 75.4 |
| 2000 | 75.6 |
| 2001 | 71.1 |
| 2002 | 73.41 |
| 2003 | 67.96 |
| 2004 | 65.04 |
| 2005 | 61.91 |
| 2006 | 62.61 |
| 2007 | 63.19 |
| 2008 | 61.75 |
| 2009 | |
| 2010 | 58.62 |
| 2011 | 64.13 |
| 2012 | 64.68 |
| 2013 | 64.99 |
| 2014 | 61.83 |
| 2015 | 58.5 |
| 2016 | 57.07 |
| 2017 | 56.85 |
| 2018 | 58.08 |