| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.68 | 81 |
| 2015 | 7.61 | 82 |
| 2014 | 7.56 | 81 |
| 2013 | 7.54 | 82 |
| 2012 | 7.56 | 82 |
| 2011 | 7.59 | 86 |
| 2010 | 7.61 | 89 |
| 2009 | 7.65 | 89 |
| 2008 | 7.69 | 88 |
| 2007 | 7.72 | 87 |
| 2006 | 7.75 | 87 |
| 2005 | 7.77 | 90 |
| 2004 | 7.77 | 90 |
| 2003 | 7.75 | 90 |
| 2002 | 7.72 | 90 |
| 2001 | 7.68 | 90 |
| 2000 | 7.62 | 89 |
| 1999 | 7.56 | 89 |
| 1998 | 7.49 | 88 |
| 1997 | 7.41 | 86 |
| 1996 | 7.3 | 83 |
| 1995 | 7.18 | 81 |
| 1994 | 7.1 | 80 |
| 1993 | 7 | 77 |
| 1992 | 6.88 | 76 |
| 1991 | 6.75 | 74 |
| 1990 | 6.62 | 72 |
| 1989 | 6.52 | 69 |
| 1988 | 6.43 | 64 |
| 1987 | 6.34 | 62 |
| 1986 | 6.23 | 58 |