| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 2.6 | 95 |
| 2014 | 1.49 | 135 |
| 2013 | 3.33 | 91 |
| 2012 | 4.4 | 73 |
| 2011 | 9.26 | 34 |
| 2010 | 16.77 | 13 |
| 2009 | 10.89 | 24 |
| 2008 | -4.02 | 187 |
| 2007 | 9.51 | 48 |
| 2006 | 4.65 | 89 |
| 2005 | 9.36 | 26 |
| 2004 | 7.73 | 32 |
| 2003 | 27.76 | 4 |
| 2002 | 17.9 | 5 |
| 2001 | 64.38 | 2 |
| 2000 | 14.77 | 9 |
| 1999 | 24.84 | 4 |
| 1998 | 74.12 | 1 |
| 1997 | 12.08 | 10 |
| 1996 | 161.82 | 1 |
| 1995 | 89.48 | 1 |
| 1994 | 16.86 | 2 |
| 1993 | 16.39 | 2 |
| 1992 | 4.47 | 17 |
| 1991 | 37.26 | 1 |
| 1990 | 9.88 | 5 |
| 1989 | 1.01 | 55 |
| 1988 | 0.5 | 74 |
| 1987 | 1.8 | 30 |
| 1986 | 7.37 | 3 |