| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 30.29 | 47 |
| 2015 | 29.61 | 59 |
| 2014 | 28.84 | 67 |
| 2013 | 28.34 | 75 |
| 2012 | 30.38 | 61 |
| 2011 | 29.33 | 70 |
| 2010 | 30.11 | 62 |
| 2009 | 32.05 | 52 |
| 2008 | 29.73 | 68 |
| 2007 | 31.69 | 60 |
| 2006 | 33.29 | 56 |
| 2005 | 34.76 | 42 |
| 2004 | 34.56 | 46 |
| 2003 | 37.32 | 29 |
| 2002 | 40.5 | 21 |
| 2001 | 37.99 | 28 |
| 2000 | 35.68 | 38 |
| 1999 | 35.93 | 28 |
| 1998 | 34.88 | 27 |
| 1997 | 33.82 | 36 |
| 1996 | 34.04 | 39 |
| 1995 | 34.59 | 37 |
| 1994 | 34.86 | 35 |
| 1993 | 35.32 | 36 |
| 1992 | 37.59 | 34 |
| 1991 | 39.02 | 25 |