| 年度 | 实际值 |
|---|---|
| 1993 | 2.5 |
| 1994 | |
| 1995 | 13.4 |
| 1996 | 14.3 |
| 1997 | 15.9 |
| 1998 | 16.4 |
| 1999 | 25.1 |
| 2000 | 25.8 |
| 2001 | 1.95333333333333 |
| 2002 | |
| 2003 | 29.2 |
| 2004 | 29.86 |
| 2005 | 30 |
| 2006 | 31.79 |
| 2007 | 32.51 |
| 2008 | 35.73 |
| 2009 | |
| 2010 | 39.25 |
| 2011 | 36.27 |
| 2012 | 37.1 |
| 2013 | 36.88 |
| 2014 | 37.15 |
| 2015 | 36.72 |
| 2016 | 37.03 |
| 2017 | 37.36 |
| 2018 | 37.74 |