| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 20.19 | 7 |
| 2015 | 19.95 | 7 |
| 2014 | 19.61 | 7 |
| 2013 | 19.25 | 6 |
| 2012 | 18.88 | 5 |
| 2011 | 18.58 | 5 |
| 2010 | 18.35 | 5 |
| 2009 | 18.19 | 5 |
| 2008 | 18.11 | 4 |
| 2007 | 18.06 | 4 |
| 2006 | 17.98 | 4 |
| 2005 | 17.82 | 4 |
| 2004 | 17.64 | 4 |
| 2003 | 17.39 | 4 |
| 2002 | 17.09 | 6 |
| 2001 | 16.75 | 8 |
| 2000 | 16.38 | 8 |
| 1999 | 16.07 | 8 |
| 1998 | 15.74 | 10 |
| 1997 | 15.4 | 11 |
| 1996 | 15.06 | 13 |
| 1995 | 14.74 | 13 |
| 1994 | 14.45 | 15 |
| 1993 | 14.18 | 15 |
| 1992 | 13.94 | 15 |
| 1991 | 13.73 | 13 |
| 1990 | 13.55 | 13 |
| 1989 | 13.26 | 14 |
| 1988 | 13.05 | 14 |
| 1987 | 12.91 | 13 |
| 1986 | 12.82 | 12 |