| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.88 | 35 |
| 2015 | 2.43 | 101 |
| 2014 | 1.94 | 123 |
| 2013 | 2.01 | 117 |
| 2012 | 1.78 | 132 |
| 2011 | 1.28 | 149 |
| 2010 | 1.91 | 128 |
| 2009 | 2.77 | 100 |
| 2008 | 6.57 | 69 |
| 2007 | 5.89 | 85 |
| 2006 | 8.91 | 47 |
| 2005 | 6.52 | 43 |
| 2004 | 8.45 | 29 |
| 2003 | 3.08 | 74 |
| 2002 | 2.48 | 98 |
| 2001 | 2.84 | 80 |
| 2000 | 2.77 | 94 |
| 1999 | 2.88 | 85 |
| 1998 | 4.84 | 45 |
| 1997 | 3.39 | 57 |
| 1996 | 0.71 | 119 |
| 1995 | 1.11 | 92 |
| 1994 | 1.13 | 81 |
| 1993 | 0.36 | 113 |
| 1992 | 0.31 | 100 |
| 1991 | 0.14 | 117 |
| 1990 | 0 | 131 |