| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 18.94 | 16 |
| 2015 | 18.37 | 17 |
| 2014 | 17.81 | 19 |
| 2013 | 17.18 | 21 |
| 2012 | 16.55 | 22 |
| 2011 | 16 | 23 |
| 2010 | 15.55 | 25 |
| 2009 | 14.95 | 27 |
| 2008 | 14.48 | 28 |
| 2007 | 14.13 | 32 |
| 2006 | 13.84 | 32 |
| 2005 | 13.54 | 33 |
| 2004 | 13.25 | 34 |
| 2003 | 12.96 | 34 |
| 2002 | 12.69 | 35 |
| 2001 | 12.45 | 35 |
| 2000 | 12.23 | 37 |
| 1999 | 12.07 | 37 |
| 1998 | 11.91 | 37 |
| 1997 | 11.75 | 37 |
| 1996 | 11.6 | 38 |
| 1995 | 11.44 | 36 |
| 1994 | 11.26 | 36 |
| 1993 | 11.09 | 36 |
| 1992 | 10.92 | 37 |
| 1991 | 10.75 | 36 |
| 1990 | 10.56 | 36 |
| 1989 | 10.4 | 36 |
| 1988 | 10.23 | 35 |
| 1987 | 10.04 | 36 |
| 1986 | 9.88 | 37 |