| 年度 | 实际值 |
|---|---|
| 1992 | 5.8 |
| 1993 | |
| 1994 | |
| 1995 | 5.7 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 3.4793 |
| 2000 | 3.3597 |
| 2001 | 5.4643 |
| 2002 | 5.4442 |
| 2003 | 5.4293 |
| 2004 | 5.4038 |
| 2005 | 5.3737 |
| 2006 | 5.3263 |
| 2007 | 5.2556 |
| 2008 | 5.2516 |
| 2009 | 5.2475 |
| 2010 | 5.2281 |
| 2011 | 5.2573 |
| 2012 | 5.3039 |
| 2013 | 5.4872 |
| 2014 | 5.6454 |
| 2015 | 5.6261 |