| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.22 | 85 |
| 2015 | 7.16 | 84 |
| 2014 | 7.15 | 83 |
| 2013 | 7.15 | 82 |
| 2012 | 7.18 | 81 |
| 2011 | 7.21 | 78 |
| 2010 | 7.25 | 76 |
| 2009 | 7.34 | 72 |
| 2008 | 7.44 | 71 |
| 2007 | 7.54 | 70 |
| 2006 | 7.62 | 67 |
| 2005 | 7.66 | 66 |
| 2004 | 7.71 | 64 |
| 2003 | 7.72 | 63 |
| 2002 | 7.71 | 61 |
| 2001 | 7.72 | 59 |
| 2000 | 7.77 | 59 |
| 1999 | 7.79 | 57 |
| 1998 | 7.86 | 57 |
| 1997 | 7.94 | 56 |
| 1996 | 7.99 | 56 |
| 1995 | 7.96 | 56 |
| 1994 | 8.02 | 55 |
| 1993 | 8.02 | 55 |
| 1992 | 7.96 | 52 |
| 1991 | 7.91 | 52 |
| 1990 | 7.89 | 52 |
| 1989 | 7.35 | 52 |
| 1988 | 6.92 | 54 |
| 1987 | 6.6 | 56 |
| 1986 | 6.38 | 56 |