| 年度 | 实际值 |
|---|---|
| 1993 | 26.8 |
| 1994 | |
| 1995 | 31.1 |
| 1996 | 33.8 |
| 1997 | 32.5 |
| 1998 | 32.9 |
| 1999 | 33.3 |
| 2000 | 38.4 |
| 2001 | 2.64666666666667 |
| 2002 | |
| 2003 | 39.96 |
| 2004 | 39.76 |
| 2005 | 41 |
| 2006 | 39.5 |
| 2007 | 40.39 |
| 2008 | 40.45 |
| 2009 | |
| 2010 | 40.54 |
| 2011 | 41.11 |
| 2012 | 42.43 |
| 2013 | 43.2 |
| 2014 | 43.54 |
| 2015 | 43.71 |
| 2016 | 44.08 |
| 2017 | |
| 2018 | 44.91 |