| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 9 | 62 |
| 2015 | 8.183 | 82 |
| 2014 | 7.5 | 95 |
| 2013 | 7.5 | 100 |
| 2012 | 7.708 | 101 |
| 2011 | 7.969 | 97 |
| 2010 | 9.283 | 89 |
| 2009 | 11.938 | 66 |
| 2008 | 12.438 | 69 |
| 2007 | 11.75 | 75 |
| 2006 | 10.918 | 81 |
| 2005 | 9.104 | 99 |
| 2004 | 9.313 | 98 |
| 2003 | 11.167 | 91 |
| 2002 | 12.479 | 82 |
| 2001 | 15.667 | 66 |
| 2000 | 16.5 | 64 |
| 1999 | 17.042 | 65 |
| 1998 | 17.333 | 66 |
| 1997 | 15.333 | 74 |
| 1996 | 15.792 | 75 |
| 1995 | 15.167 | 77 |
| 1994 | 15.979 | 59 |
| 1993 | 15.5 | 63 |
| 1992 | 15.333 | 58 |
| 1991 | 13.17 | 63 |
| 1990 | 12.87 | 63 |
| 1989 | 13.313 | 58 |
| 1988 | 12.583 | 53 |
| 1987 | 11.5 | 60 |
| 1986 | 12 | 61 |