| 年度 | 实际值 |
|---|---|
| 1995 | 58 |
| 1996 | 55.8 |
| 1997 | 27.5 |
| 1998 | 56.1 |
| 1999 | 54.6 |
| 2000 | 54.6 |
| 2001 | 54.55 |
| 2002 | 55.51 |
| 2003 | 56.84 |
| 2004 | 57.45 |
| 2005 | 57.7 |
| 2006 | 57.7 |
| 2007 | 53.49 |
| 2008 | 57.57 |
| 2009 | |
| 2010 | 48.81 |
| 2011 | 49.83 |
| 2012 | 49.44 |
| 2013 | 47.91 |
| 2014 | 48.14 |
| 2015 | 47.02 |
| 2016 | 40.98 |
| 2017 | 41.66 |
| 2018 | 41.57 |