| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 18.53 | 18 |
| 2015 | 17.99 | 22 |
| 2014 | 17.49 | 22 |
| 2013 | 16.95 | 22 |
| 2012 | 16.42 | 23 |
| 2011 | 15.91 | 24 |
| 2010 | 15.44 | 26 |
| 2009 | 15.07 | 25 |
| 2008 | 14.74 | 26 |
| 2007 | 14.46 | 30 |
| 2006 | 14.23 | 31 |
| 2005 | 14.04 | 31 |
| 2004 | 13.95 | 31 |
| 2003 | 13.92 | 29 |
| 2002 | 13.92 | 29 |
| 2001 | 13.9 | 27 |
| 2000 | 13.8 | 26 |
| 1999 | 13.77 | 24 |
| 1998 | 13.69 | 23 |
| 1997 | 13.55 | 24 |
| 1996 | 13.39 | 24 |
| 1995 | 13.22 | 24 |
| 1994 | 13.17 | 24 |
| 1993 | 13.1 | 21 |
| 1992 | 13.01 | 19 |
| 1991 | 12.87 | 19 |
| 1990 | 12.68 | 20 |
| 1989 | 12.52 | 21 |
| 1988 | 12.29 | 21 |
| 1987 | 12.02 | 20 |
| 1986 | 11.81 | 20 |