| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 9 | 92 |
| 2015 | 8.84 | 92 |
| 2014 | 8.67 | 93 |
| 2013 | 8.57 | 94 |
| 2012 | 8.51 | 94 |
| 2011 | 8.48 | 94 |
| 2010 | 8.44 | 93 |
| 2009 | 8.29 | 92 |
| 2008 | 8.14 | 92 |
| 2007 | 7.99 | 92 |
| 2006 | 7.84 | 90 |
| 2005 | 7.69 | 87 |
| 2004 | 7.48 | 85 |
| 2003 | 7.29 | 80 |
| 2002 | 7.12 | 79 |
| 2001 | 6.96 | 79 |
| 2000 | 6.82 | 76 |
| 1999 | 6.8 | 73 |
| 1998 | 6.77 | 71 |
| 1997 | 6.73 | 71 |
| 1996 | 6.69 | 68 |
| 1995 | 6.62 | 68 |
| 1994 | 6.64 | 67 |
| 1993 | 6.64 | 67 |
| 1992 | 6.62 | 67 |
| 1991 | 6.59 | 67 |
| 1990 | 6.53 | 67 |
| 1989 | 6.5 | 67 |
| 1988 | 6.46 | 66 |
| 1987 | 6.39 | 66 |
| 1986 | 6.31 | 64 |