| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.86 | 32 |
| 2015 | 1.37 | 95 |
| 2014 | 0.54 | 132 |
| 2013 | 2.91 | 86 |
| 2012 | 3.41 | 100 |
| 2011 | 7.29 | 58 |
| 2010 | 3.68 | 85 |
| 2009 | 3.21 | 88 |
| 2008 | 7.73 | 108 |
| 2007 | 4.8 | 96 |
| 2006 | 2.49 | 130 |
| 2005 | 2.37 | 132 |
| 2004 | 2.83 | 103 |
| 2003 | 4.17 | 74 |
| 2002 | 0.76 | 144 |
| 2001 | 4.27 | 81 |
| 2000 | 1.09 | 133 |
| 1999 | 1.97 | 108 |
| 1998 | 5.71 | 78 |
| 1997 | 3.37 | 107 |
| 1996 | 3.05 | 118 |
| 1995 | 2.17 | 138 |
| 1994 | 0.82 | 151 |
| 1993 | 5.21 | 88 |
| 1992 | 4.88 | 88 |
| 1991 | 6.5 | 85 |
| 1990 | 8.19 | 70 |
| 1989 | 6.19 | 80 |
| 1988 | 11.76 | 46 |
| 1987 | 5.66 | 68 |
| 1986 | 1.8 | 95 |