| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 3.68 | 75 |
| 2014 | 7.73 | 34 |
| 2013 | 6.71 | 37 |
| 2012 | 9.75 | 29 |
| 2011 | 9.58 | 33 |
| 2010 | 8.76 | 35 |
| 2009 | 8.1 | 42 |
| 2008 | 9.26 | 41 |
| 2007 | 8.76 | 56 |
| 2006 | 7.02 | 61 |
| 2005 | 9.31 | 27 |
| 2004 | 3.82 | 74 |
| 2003 | 3.52 | 63 |
| 2002 | 6.03 | 32 |
| 2001 | 8.04 | 24 |
| 2000 | 9.42 | 17 |
| 1999 | 6.62 | 37 |
| 1998 | 6.13 | 36 |
| 1997 | 6.94 | 22 |
| 1996 | 8.36 | 13 |
| 1995 | 11.97 | 6 |
| 1994 | 19.73 | 1 |
| 1993 | 15.72 | 3 |
| 1992 | 39.81 | 1 |
| 1991 | 3.66 | 22 |
| 1990 | 1.99 | 41 |
| 1989 | -.54 | 133 |
| 1988 | 0.51 | 72 |
| 1987 | 1.23 | 42 |
| 1986 | -1.78 | 131 |