| 年度 | 实际值 |
|---|---|
| 1993 | 24 |
| 1994 | |
| 1995 | 28.5 |
| 1996 | 28.2 |
| 1997 | 32.1 |
| 1998 | 33.2 |
| 1999 | 36.3 |
| 2000 | 38.5 |
| 2001 | 2.66 |
| 2002 | |
| 2003 | 43.98 |
| 2004 | 44.78 |
| 2005 | 44 |
| 2006 | 42.17 |
| 2007 | 43.33 |
| 2008 | 44.31 |
| 2009 | |
| 2010 | 45 |
| 2011 | 40.06 |
| 2012 | 40.62 |
| 2013 | 41.14 |
| 2014 | 41.17 |
| 2015 | 41.17 |
| 2016 | 29.28 |
| 2017 | 40.79 |
| 2018 | 41.51 |