| 年度 | 实际值 |
|---|---|
| 1993 | 33.5 |
| 1994 | |
| 1995 | 36.3 |
| 1996 | 36.7 |
| 1997 | 37.3 |
| 1998 | 37.7 |
| 1999 | 37.5 |
| 2000 | 37.2 |
| 2001 | 2.58666666666667 |
| 2002 | |
| 2003 | 39.75 |
| 2004 | 43.5 |
| 2005 | 45 |
| 2006 | 46.17 |
| 2007 | 46.28 |
| 2008 | 46.37 |
| 2009 | |
| 2010 | 46.5 |
| 2011 | 44.31 |
| 2012 | 47.92 |
| 2013 | 47.95 |
| 2014 | 49.01 |
| 2015 | 45.9 |
| 2016 | 45.95 |
| 2017 | 45.89 |
| 2018 | 45.77 |