| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 6.08 | 98 |
| 2015 | 5.86 | 99 |
| 2014 | 5.66 | 101 |
| 2013 | 5.47 | 101 |
| 2012 | 5.28 | 102 |
| 2011 | 5.1 | 104 |
| 2010 | 4.94 | 105 |
| 2009 | 4.86 | 108 |
| 2008 | 4.78 | 110 |
| 2007 | 4.67 | 111 |
| 2006 | 4.55 | 111 |
| 2005 | 4.4 | 113 |
| 2004 | 4.31 | 114 |
| 2003 | 4.23 | 114 |
| 2002 | 4.13 | 117 |
| 2001 | 4.02 | 119 |
| 2000 | 3.91 | 119 |
| 1999 | 3.86 | 121 |
| 1998 | 3.84 | 121 |
| 1997 | 3.83 | 121 |
| 1996 | 3.82 | 119 |
| 1995 | 3.8 | 118 |
| 1994 | 3.78 | 119 |
| 1993 | 3.76 | 119 |
| 1992 | 3.73 | 121 |
| 1991 | 3.71 | 122 |
| 1990 | 3.68 | 123 |
| 1989 | 3.68 | 121 |
| 1988 | 3.69 | 119 |
| 1987 | 3.7 | 115 |
| 1986 | 3.71 | 115 |