| 年度 | 实际值 |
|---|---|
| 1995 | 48.3 |
| 1996 | 49.8 |
| 1997 | 49.37 |
| 1998 | 48.8 |
| 1999 | 47.1 |
| 2000 | 47.1 |
| 2001 | 46.46 |
| 2002 | 46.08 |
| 2003 | 46.51 |
| 2004 | 48.18 |
| 2005 | 44.91 |
| 2006 | 46.15 |
| 2007 | 46.02 |
| 2008 | 42.77 |
| 2009 | |
| 2010 | 45.32 |
| 2011 | 46.27 |
| 2012 | 45.78 |
| 2013 | 45.01 |
| 2014 | 41.44 |
| 2015 | 39.98 |
| 2016 | 38.61 |
| 2017 | |
| 2018 | 39.14 |