| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 1.624 | 89 |
| 2015 | 1.899 | 98 |
| 2014 | 2.024 | 109 |
| 2013 | 2.021 | 115 |
| 2012 | 2.042 | 122 |
| 2011 | 2.161 | 119 |
| 2010 | 2.337 | 118 |
| 2009 | 2.831 | 116 |
| 2008 | 4.806 | 84 |
| 2007 | 5.447 | 75 |
| 2006 | 4.924 | 72 |
| 2005 | 3.469 | 97 |
| 2004 | 2.655 | 109 |
| 2003 | 2.418 | 120 |
| 2002 | 3.152 | 113 |
| 2001 | 4.475 | 105 |
| 2000 | 5.891 | 89 |
| 1999 | 5.764 | 90 |
| 1998 | 6.318 | 96 |
| 1997 | 5.925 | 94 |
| 1996 | 6.048 | 99 |
| 1995 | 6.533 | 88 |
| 1994 | 5.701 | 91 |
| 1993 | 7.073 | 78 |
| 1992 | 7.592 | 66 |
| 1989 | 7.403 | 73 |
| 1988 | 5.298 | 88 |
| 1987 | 5.733 | 80 |
| 1986 | 6.804 | 70 |