| 年度 | 实际值 |
|---|---|
| 1995 | 63.4 |
| 1996 | 59.1 |
| 1997 | 57.5 |
| 1998 | 53.7 |
| 1999 | 53.6 |
| 2000 | 50.7 |
| 2001 | 53.48 |
| 2002 | 54.15 |
| 2003 | 57.39 |
| 2004 | 59.66 |
| 2005 | 53.86 |
| 2006 | 52.23 |
| 2007 | 52.46 |
| 2008 | 52.92 |
| 2009 | |
| 2010 | 48.69 |
| 2011 | 50.73 |
| 2012 | 50.7 |
| 2013 | 47.09 |
| 2014 | 44.47 |
| 2015 | 41.77 |
| 2016 | 36.52 |
| 2017 | |
| 2018 | 36.52 |