| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 28.76 | 59 |
| 2015 | 28.89 | 64 |
| 2014 | 28.12 | 72 |
| 2013 | 26.98 | 86 |
| 2012 | 26.1 | 95 |
| 2011 | 26.02 | 98 |
| 2010 | 28.06 | 81 |
| 2009 | 27.43 | 81 |
| 2008 | 26.17 | 100 |
| 2007 | 27.49 | 89 |
| 2006 | 26.72 | 96 |
| 2005 | 27.42 | 88 |
| 2004 | 25.61 | 102 |
| 2003 | 26.06 | 94 |
| 2002 | 24.33 | 107 |
| 2001 | 24.53 | 106 |
| 2000 | 24.51 | 105 |
| 1999 | 25.95 | 93 |
| 1998 | 26.24 | 92 |
| 1997 | 26.37 | 95 |
| 1996 | 28.55 | 85 |
| 1995 | 28.92 | 87 |
| 1994 | 28 | 75 |
| 1993 | 29.66 | 68 |
| 1992 | 32.78 | 51 |
| 1991 | 35.55 | 42 |
| 1990 | 34.64 | 38 |
| 1989 | 33.67 | 43 |
| 1988 | 34.2 | 37 |
| 1987 | 35.83 | 31 |
| 1986 | 36.23 | 26 |