| 年度 | 实际值 |
|---|---|
| 1993 | 6.8 |
| 1994 | |
| 1995 | 26.9 |
| 1996 | 29.1 |
| 1997 | 29.4 |
| 1998 | 28.8 |
| 1999 | 26.9 |
| 2000 | 26.1 |
| 2001 | 1.70666666666667 |
| 2002 | |
| 2003 | 35.97 |
| 2004 | 36.45 |
| 2005 | 40 |
| 2006 | 41.6 |
| 2007 | 44.03 |
| 2008 | 42.38 |
| 2009 | |
| 2010 | 42.35 |
| 2011 | 42.19 |
| 2012 | 41.31 |
| 2013 | 40.93 |
| 2014 | 41.94 |
| 2015 | 40.8 |
| 2016 | 41.2 |
| 2017 | 40.94 |
| 2018 | 43 |