| 年度 | 实际值 |
|---|---|
| 1992 | 12.6 |
| 1993 | |
| 1994 | |
| 1995 | 14 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 13.2 |
| 2000 | 13.5685 |
| 2001 | 15.7668 |
| 2002 | 15.8741 |
| 2003 | 15.9639 |
| 2004 | 16.3668 |
| 2005 | 19.9953 |
| 2006 | 18.6961 |
| 2007 | 19.7346 |
| 2008 | 20.7355 |
| 2009 | 20.8051 |
| 2010 | 24.5967 |
| 2011 | 23.4149 |
| 2012 | 23.3497 |
| 2013 | 22.8179 |
| 2014 | 24.3456 |
| 2015 | 24.366 |