| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 33.43 | 27 |
| 2015 | 34.08 | 34 |
| 2014 | 38.6 | 21 |
| 2013 | 39.03 | 24 |
| 2012 | 39.59 | 25 |
| 2011 | 38.98 | 28 |
| 2010 | 36.32 | 41 |
| 2009 | 34.34 | 38 |
| 2008 | 39.33 | 33 |
| 2007 | 36.23 | 44 |
| 2006 | 35.64 | 44 |
| 2005 | 33.4 | 49 |
| 2004 | 31.79 | 58 |
| 2003 | 30.1 | 66 |
| 2002 | 31.34 | 59 |
| 2001 | 31.55 | 56 |
| 2000 | 35.65 | 39 |
| 1999 | 27.02 | 87 |
| 1998 | 24.37 | 107 |
| 1997 | 24.39 | 106 |
| 1996 | 25.2 | 102 |
| 1995 | 25.45 | 101 |
| 1994 | 26.42 | 82 |
| 1993 | 27.38 | 77 |
| 1992 | 31.34 | 57 |
| 1991 | 30.18 | 67 |
| 1990 | 29.87 | 65 |
| 1989 | 28.95 | 60 |
| 1988 | 29.62 | 53 |
| 1987 | 27 | 63 |
| 1986 | 27.19 | 56 |