| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 18.52 | 33 |
| 2015 | 22.4 | 29 |
| 2014 | 21.11 | 34 |
| 2013 | 21.92 | 36 |
| 2012 | 21.46 | 37 |
| 2011 | 21.35 | 40 |
| 2010 | 21.03 | 39 |
| 2009 | 23.97 | 33 |
| 2008 | 26.35 | 25 |
| 2007 | 24.41 | 33 |
| 2006 | 27.05 | 28 |
| 2005 | 34.6 | 17 |
| 2004 | 31.31 | 23 |
| 2003 | 31.44 | 26 |
| 2002 | 30.82 | 27 |
| 2001 | 30.3 | 26 |
| 2000 | 31.09 | 26 |
| 1999 | 34.64 | 24 |
| 1998 | 34.61 | 25 |
| 1997 | 35.45 | 23 |
| 1996 | 38.89 | 22 |
| 1995 | 41.23 | 19 |
| 1994 | 36.99 | 23 |
| 1993 | 36.15 | 26 |
| 1992 | 40.75 | 15 |
| 1991 | 38.38 | 18 |
| 1990 | 38.08 | 16 |
| 1989 | 39.92 | 14 |
| 1988 | 26 | 38 |
| 1987 | 29.95 | 29 |
| 1986 | 26.67 | 34 |