| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 28.94 | 56 |
| 2015 | 29.64 | 57 |
| 2014 | 29.79 | 62 |
| 2013 | 29.69 | 65 |
| 2012 | 30.06 | 66 |
| 2011 | 31.1 | 56 |
| 2010 | 30.72 | 56 |
| 2009 | 32.08 | 50 |
| 2008 | 33.84 | 51 |
| 2007 | 31.62 | 61 |
| 2006 | 28.98 | 83 |
| 2005 | 28.61 | 81 |
| 2004 | 28.6 | 82 |
| 2003 | 27.05 | 87 |
| 2002 | 27.09 | 87 |
| 2001 | 25.76 | 98 |
| 2000 | 25.55 | 97 |
| 1999 | 25.92 | 94 |
| 1998 | 26.44 | 90 |
| 1997 | 25.83 | 98 |
| 1996 | 26.13 | 96 |
| 1995 | 28.92 | 86 |
| 1994 | 29.13 | 67 |
| 1993 | 27.44 | 76 |
| 1992 | 27.47 | 77 |
| 1991 | 24.39 | 89 |
| 1990 | 26.24 | 80 |
| 1989 | 25.24 | 73 |
| 1988 | 23.93 | 74 |
| 1987 | 26.24 | 66 |
| 1986 | 26.6 | 62 |