| 年度 | 实际值 |
|---|---|
| 1992 | .2 |
| 1993 | .3 |
| 1994 | |
| 1995 | -.08 |
| 1996 | 1.69 |
| 1997 | 3.81 |
| 1998 | 6.23 |
| 1999 | 5.02 |
| 2000 | 4.54 |
| 2001 | 4.69 |
| 2002 | 5.89 |
| 2003 | 4.06 |
| 2004 | 6.59 |
| 2005 | 4.35 |
| 2006 | 3.15 |
| 2007 | 2.55 |
| 2008 | 3.27 |
| 2009 | |
| 2010 | 2.35 |
| 2011 | 5 |
| 2012 | 3 |
| 2013 | 5 |
| 2014 | 8.2 |
| 2015 | 7.26 |
| 2016 | 8.57 |
| 2017 | 7.35 |
| 2018 | 6.5 |