| 年度 | 实际值 |
|---|---|
| 1992 | 1 |
| 1993 | |
| 1994 | |
| 1995 | .82 |
| 1996 | 2.14 |
| 1997 | 2.57 |
| 1998 | 6.43 |
| 1999 | 3.06 |
| 2000 | 3.89 |
| 2001 | 3.96 |
| 2002 | 3.59 |
| 2003 | 3.13 |
| 2004 | 3.72 |
| 2005 | 4.42 |
| 2006 | 4.44 |
| 2007 | 3.97 |
| 2008 | 5.05 |
| 2009 | |
| 2010 | 5.41 |
| 2011 | 6.8 |
| 2012 | 6.1 |
| 2013 | 4.7 |
| 2014 | 10 |
| 2015 | 9.72 |
| 2016 | 10.51 |
| 2017 | -1.98 |
| 2018 | 6.81 |