| 年度 | 实际值 |
|---|---|
| 1992 | 3.1 |
| 1993 | |
| 1994 | |
| 1995 | 2.8 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 3.2966 |
| 2000 | 3.3269 |
| 2001 | 4.0294 |
| 2002 | 4.0306 |
| 2003 | 4.0365 |
| 2004 | 3.4144 |
| 2005 | 4.0847 |
| 2006 | 4.0579 |
| 2007 | 4.0637 |
| 2008 | 3.9527 |
| 2009 | 3.3879 |
| 2010 | 3.9584 |
| 2011 | 3.9567 |
| 2012 | 3.9218 |
| 2013 | 5.2883 |
| 2014 | 4.9984 |
| 2015 | 5.2655 |