| 年度 | 实际值 |
|---|---|
| 1992 | 1.7 |
| 1993 | |
| 1994 | |
| 1995 | 1.4 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 1.6688 |
| 2000 | 1.7778 |
| 2001 | 1.7691 |
| 2002 | 1.9007 |
| 2003 | 1.9506 |
| 2004 | 1.9751 |
| 2005 | 2.1172 |
| 2006 | 2.2192 |
| 2007 | 2.1705 |
| 2008 | 2.1904 |
| 2009 | 2.1854 |
| 2010 | 2.217 |
| 2011 | 2.2764 |
| 2012 | 2.291 |
| 2013 | 2.3823 |
| 2014 | 2.2732 |
| 2015 | 2.4878 |