| 年度 | 实际值 |
|---|---|
| 1992 | 11 |
| 1993 | 9.2 |
| 1994 | |
| 1995 | 8.98 |
| 1996 | 7.32 |
| 1997 | 10.75 |
| 1998 | 3.91 |
| 1999 | 5.2 |
| 2000 | 11.11 |
| 2001 | 5.55 |
| 2002 | 6.83 |
| 2003 | 6.12 |
| 2004 | 7.81 |
| 2005 | 2.3 |
| 2006 | 4.34 |
| 2007 | 4.43 |
| 2008 | 3.35 |
| 2009 | |
| 2010 | 2.82 |
| 2011 | 2.2 |
| 2012 | 1.3 |
| 2013 | 5.3 |
| 2014 | .6 |
| 2015 | 2.41 |
| 2016 | 3.6 |
| 2017 | -0.08 |
| 2018 | 2.33 |