| 年度 | 实际值 |
|---|---|
| 1992 | 3.7 |
| 1993 | |
| 1994 | |
| 1995 | 3.7 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 3.5449 |
| 2000 | 3.8524 |
| 2001 | 3.6741 |
| 2002 | 4.2772 |
| 2003 | 4.1995 |
| 2004 | 4.3142 |
| 2005 | 4.3376 |
| 2006 | 4.2903 |
| 2007 | 4.3521 |
| 2008 | 4.2826 |
| 2009 | 4.3081 |
| 2010 | 4.1984 |
| 2011 | 4.2828 |
| 2012 | 4.3228 |
| 2013 | 4.2124 |
| 2014 | 4.1028 |
| 2015 | 4.3659 |