| 年度 | 实际值 |
|---|---|
| 1992 | 3.1 |
| 1993 | |
| 1994 | |
| 1995 | 3.5 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 3.2277 |
| 2000 | 3.3151 |
| 2001 | 3.1934 |
| 2002 | 3.2185 |
| 2003 | 3.1181 |
| 2004 | 3.4808 |
| 2005 | 3.5364 |
| 2006 | 3.6729 |
| 2007 | 3.6425 |
| 2008 | 3.3322 |
| 2009 | 3.1724 |
| 2010 | 3.1641 |
| 2011 | 3.2255 |
| 2012 | 3.1853 |
| 2013 | 3.2313 |
| 2014 | 3.3315 |
| 2015 | 3.2278 |