| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 20.62 | 65 |
| 2014 | 20.94 | 66 |
| 2013 | 20.41 | 79 |
| 2012 | 22.22 | 72 |
| 2011 | 24.37 | 61 |
| 2010 | 20.92 | 75 |
| 2009 | 21.6 | 72 |
| 2008 | 27.5 | 50 |
| 2007 | 28.84 | 51 |
| 2006 | 19.78 | 78 |
| 2005 | 19.08 | 82 |
| 2004 | 20.5 | 66 |
| 2003 | 28.54 | 39 |
| 2002 | 24.69 | 48 |
| 2001 | 24.61 | 45 |
| 2000 | 37.58 | 26 |
| 1999 | 18.23 | 63 |
| 1998 | 26.39 | 39 |
| 1997 | 21.62 | 50 |
| 1996 | 23.71 | 37 |
| 1995 | 22.78 | 38 |
| 1994 | 22.65 | 44 |
| 1993 | 26.85 | 32 |
| 1992 | 24.91 | 34 |
| 1991 | 23.67 | 33 |
| 1990 | 25.97 | 28 |
| 1989 | 26.11 | 30 |
| 1988 | 24.83 | 35 |
| 1987 | 26.13 | 32 |
| 1986 | 20.5 | 37 |