| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 6.92 | 69 |
| 2015 | 6.96 | 70 |
| 2014 | 6.98 | 74 |
| 2013 | 6.98 | 74 |
| 2012 | 6.96 | 75 |
| 2011 | 6.9 | 76 |
| 2010 | 6.82 | 72 |
| 2009 | 6.9 | 72 |
| 2008 | 6.95 | 73 |
| 2007 | 6.97 | 73 |
| 2006 | 6.97 | 74 |
| 2005 | 6.94 | 73 |
| 2004 | 7.03 | 76 |
| 2003 | 7.09 | 78 |
| 2002 | 7.13 | 80 |
| 2001 | 7.15 | 81 |
| 2000 | 7.14 | 82 |
| 1999 | 7.23 | 84 |
| 1998 | 7.3 | 84 |
| 1997 | 7.35 | 85 |
| 1996 | 7.38 | 86 |
| 1995 | 7.37 | 88 |
| 1994 | 7.45 | 88 |
| 1993 | 7.52 | 91 |
| 1992 | 7.56 | 95 |
| 1991 | 7.59 | 100 |
| 1990 | 7.6 | 102 |
| 1989 | 7.61 | 100 |
| 1988 | 7.61 | 104 |
| 1987 | 7.59 | 103 |
| 1986 | 7.55 | 103 |