| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 19.15 | 14 |
| 2015 | 18.82 | 15 |
| 2014 | 18.54 | 13 |
| 2013 | 18.26 | 11 |
| 2012 | 17.99 | 11 |
| 2011 | 17.74 | 11 |
| 2010 | 17.52 | 11 |
| 2009 | 17.38 | 11 |
| 2008 | 17.27 | 10 |
| 2007 | 17.16 | 11 |
| 2006 | 16.99 | 11 |
| 2005 | 16.76 | 11 |
| 2004 | 16.53 | 12 |
| 2003 | 16.21 | 13 |
| 2002 | 15.82 | 14 |
| 2001 | 15.41 | 14 |
| 2000 | 15.02 | 17 |
| 1999 | 14.74 | 20 |
| 1998 | 14.5 | 20 |
| 1997 | 14.25 | 21 |
| 1996 | 13.96 | 22 |
| 1995 | 13.6 | 22 |
| 1994 | 13.26 | 22 |
| 1993 | 12.86 | 24 |
| 1992 | 12.43 | 25 |
| 1991 | 12.03 | 25 |
| 1990 | 11.66 | 25 |
| 1989 | 11.54 | 24 |
| 1988 | 11.46 | 24 |
| 1987 | 11.42 | 23 |
| 1986 | 11.42 | 23 |