| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.79 | 24 |
| 2015 | 2.03 | 47 |
| 2014 | 2.82 | 30 |
| 2013 | 5.61 | 6 |
| 2011 | 5.02 | 7 |
| 2010 | 5.78 | 6 |
| 2009 | 7.99 | 3 |
| 2008 | 5.91 | 7 |
| 2007 | 4.5 | 9 |
| 2006 | 3 | 27 |
| 2005 | 0.83 | 131 |
| 2004 | 1.14 | 117 |
| 2003 | 1.5 | 90 |
| 2002 | 1.73 | 75 |
| 2001 | 1.53 | 83 |
| 2000 | 1.54 | 80 |
| 1999 | 1.37 | 96 |
| 1998 | 0.92 | 119 |
| 1997 | 1.08 | 113 |
| 1996 | 1.54 | 86 |
| 1995 | 1.39 | 99 |
| 1994 | 1.88 | 77 |
| 1993 | 2.68 | 50 |
| 1992 | 1.88 | 82 |
| 1990 | 1.98 | 80 |
| 1989 | 3.94 | 32 |
| 1988 | 5.25 | 20 |
| 1987 | 2.95 | 51 |
| 1986 | 4.57 | 21 |