| 年度 | 实际值 |
|---|---|
| 1992 | 20.5 |
| 1993 | |
| 1994 | |
| 1995 | 20.6 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 20.6 |
| 2000 | 20.6716 |
| 2001 | 20.6749 |
| 2002 | 20.6723 |
| 2003 | 20.7526 |
| 2004 | 20.8112 |
| 2005 | 16.43 |
| 2006 | 16.4146 |
| 2007 | 16.43 |
| 2008 | 16.4604 |
| 2009 | 20.925 |
| 2010 | 21.0588 |
| 2011 | 21.1698 |
| 2012 | 20.9888 |
| 2013 | 21.1807 |
| 2014 | 16.42 |
| 2015 | 16.4661 |
| 2016 | 21 |
| 2017 | 22 |