| 年度 | 实际值 |
|---|---|
| 1995 | 64.1 |
| 1996 | 61.6 |
| 1997 | 50.34 |
| 1998 | 52.4 |
| 1999 | 51.1 |
| 2000 | 51 |
| 2001 | 50.48 |
| 2002 | 49.76 |
| 2003 | 51.98 |
| 2004 | 52.95 |
| 2005 | 56.27 |
| 2006 | 58.05 |
| 2007 | 57.42 |
| 2008 | 59.04 |
| 2009 | |
| 2010 | 56.44 |
| 2011 | 60.53 |
| 2012 | 60.47 |
| 2013 | 58.31 |
| 2014 | 59.41 |
| 2015 | 58.74 |
| 2016 | 57.48 |
| 2017 | 54.18 |
| 2018 | 53.43 |