| 年度 | 实际值 |
|---|---|
| 1992 | 13.4 |
| 1993 | |
| 1994 | |
| 1995 | 13.8 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 14.1 |
| 2000 | 14.4577 |
| 2001 | 14.64 |
| 2002 | 14.9385 |
| 2003 | 15.7911 |
| 2004 | 15.981 |
| 2005 | 15.78 |
| 2006 | 15.57 |
| 2007 | 15.27 |
| 2008 | 15.38 |
| 2009 | 16.45 |
| 2010 | 16.586 |
| 2011 | 16.6938 |
| 2012 | 16.5332 |
| 2013 | 16.6395 |
| 2014 | 15.79 |
| 2015 | 15.8399440389294 |
| 2016 | 16 |
| 2017 | 15 |