| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 16.43 | 41 |
| 2015 | 17.43 | 46 |
| 2014 | 17.74 | 47 |
| 2013 | 16.99 | 51 |
| 2012 | 16.98 | 51 |
| 2011 | 17.12 | 49 |
| 2010 | 17.5 | 50 |
| 2009 | 18.75 | 46 |
| 2008 | 18.97 | 46 |
| 2007 | 19.23 | 49 |
| 2006 | 22.14 | 43 |
| 2005 | 23.18 | 40 |
| 2004 | 24.92 | 35 |
| 2003 | 25.19 | 38 |
| 2002 | 26.34 | 34 |
| 2001 | 26.13 | 34 |
| 2000 | 27.39 | 33 |
| 1999 | 27.27 | 35 |
| 1998 | 29.53 | 36 |
| 1997 | 31.2 | 34 |
| 1996 | 31.16 | 33 |
| 1995 | 32.01 | 34 |
| 1994 | 34.87 | 29 |
| 1993 | 32.23 | 31 |
| 1992 | 34.35 | 27 |
| 1991 | 33.83 | 27 |
| 1990 | 35.28 | 20 |
| 1989 | 35.75 | 19 |
| 1988 | 38.32 | 15 |
| 1987 | 36.62 | 16 |
| 1986 | 42.11 | 10 |