| 年度 | 实际值 |
|---|---|
| 1995 | 44.2 |
| 1996 | 47.4 |
| 1997 | 46.07 |
| 1998 | 38.7 |
| 1999 | 33.1 |
| 2000 | 32.1 |
| 2001 | 32.51 |
| 2002 | 32.87 |
| 2003 | 32.19 |
| 2004 | 35.59 |
| 2005 | 38.15 |
| 2006 | 37.87 |
| 2007 | 41.37 |
| 2008 | 44.36 |
| 2009 | |
| 2010 | 44.78 |
| 2011 | 48.64 |
| 2012 | 49.89 |
| 2013 | 47.94 |
| 2014 | 48.06 |
| 2015 | 48.32 |
| 2016 | 47.35 |
| 2017 | |
| 2018 | 44.19 |