| 年度 | 实际值 |
|---|---|
| 1992 | 7 |
| 1993 | |
| 1994 | |
| 1995 | 7.9 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 9.7862 |
| 2000 | 10.2328 |
| 2001 | 10.9125 |
| 2002 | 11.9599 |
| 2003 | 12.3511 |
| 2004 | 14.3854 |
| 2005 | 14.6451 |
| 2006 | 13.299 |
| 2007 | 14.5442 |
| 2008 | 14.5973 |
| 2009 | 15.1268 |
| 2010 | 15.2097 |
| 2011 | 15.2869 |
| 2012 | 15.3487 |
| 2013 | 15.3487 |
| 2014 | 12.9952 |
| 2015 | 12.1304 |