| 年度 | 实际值 |
|---|---|
| 1992 | 2.9 |
| 1993 | |
| 1994 | |
| 1995 | 2.6 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 3.0497 |
| 2000 | 3.1807 |
| 2001 | 3.0116 |
| 2002 | 3.0238 |
| 2003 | 3.0682 |
| 2004 | 3.0495 |
| 2005 | 3.1001 |
| 2006 | 3.1409 |
| 2007 | 3.0908 |
| 2008 | 3.0698 |
| 2009 | 3.0595 |
| 2010 | 3.0855 |
| 2011 | 3.1907 |
| 2012 | 3.9172 |
| 2013 | 3.3448 |
| 2014 | 4.0738 |
| 2015 | 4.1098 |