| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 2.86 | 97 |
| 2014 | 4.35 | 64 |
| 2013 | 5.42 | 50 |
| 2012 | 3.73 | 92 |
| 2011 | 1.98 | 141 |
| 2010 | 4.33 | 95 |
| 2009 | 2.54 | 66 |
| 2008 | 6.25 | 59 |
| 2007 | 8.29 | 49 |
| 2006 | 6.47 | 78 |
| 2005 | 6.77 | 57 |
| 2004 | 6.98 | 55 |
| 2003 | 6.02 | 59 |
| 2002 | 3.61 | 94 |
| 2001 | 2.49 | 114 |
| 2000 | 5.3 | 73 |
| 1999 | 4.3 | 70 |
| 1998 | 4.79 | 64 |
| 1997 | 3.09 | 131 |
| 1996 | 4.11 | 100 |
| 1995 | 3.93 | 100 |
| 1994 | -.25 | 152 |
| 1993 | 12.87 | 7 |
| 1992 | 6.69 | 37 |
| 1991 | 11.23 | 6 |
| 1990 | 4.44 | 60 |
| 1989 | 0.36 | 133 |
| 1988 | 7 | 45 |
| 1987 | 10.4 | 14 |
| 1986 | 1.18 | 121 |