| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 8.474 | 7 |
| 2015 | 8.326 | 11 |
| 2014 | 8.239 | 14 |
| 2013 | 1.621 | 134 |
| 2012 | 0.666 | 148 |
| 2011 | 13.256 | 4 |
| 2010 | 12.134 | 10 |
| 2009 | 13.266 | 6 |
| 2008 | 4.675 | 81 |
| 2007 | 6.065 | 97 |
| 2006 | 8.157 | 46 |
| 2005 | 14.802 | 4 |
| 2004 | 10.799 | 18 |
| 2003 | 9.374 | 18 |
| 2002 | 7.233 | 27 |
| 2001 | 5.924 | 37 |
| 2000 | 12.078 | 6 |
| 1999 | 6.727 | 27 |
| 1998 | 11.185 | 7 |
| 1997 | 11.393 | 14 |
| 1996 | 13.273 | 7 |
| 1995 | 5.164 | 45 |
| 1994 | 2.424 | 80 |
| 1993 | 5.847 | 36 |
| 1992 | -.218 | 103 |
| 1991 | 1.739 | 75 |
| 1990 | 32.582 | 3 |
| 1989 | 9.628 | 15 |
| 1988 | 10.109 | 15 |
| 1987 | 14.044 | 9 |
| 1986 | 14.114 | 4 |