| 年度 | 实际值 |
|---|---|
| 1993 | 9.7 |
| 1994 | |
| 1995 | 42 |
| 1996 | 41.8 |
| 1997 | 42.4 |
| 1998 | 44.2 |
| 1999 | 46 |
| 2000 | 37.8 |
| 2001 | 2.54 |
| 2002 | |
| 2003 | 39.38 |
| 2004 | 38.82 |
| 2005 | 45 |
| 2006 | 45.8 |
| 2007 | 43.12 |
| 2008 | 44.42 |
| 2009 | |
| 2010 | 43.14 |
| 2011 | 41.5 |
| 2012 | 41.06 |
| 2013 | 40.86 |
| 2014 | 43.58 |
| 2015 | 42.63 |
| 2016 | 43.25 |
| 2017 | 41.36 |
| 2018 | 42.94 |