| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 21.18 | 27 |
| 2015 | 20.86 | 34 |
| 2014 | 20.24 | 38 |
| 2013 | 21 | 39 |
| 2012 | 22.05 | 33 |
| 2011 | 22.29 | 36 |
| 2010 | 23.89 | 31 |
| 2009 | 37.05 | 9 |
| 2008 | 32.85 | 14 |
| 2007 | 32.71 | 14 |
| 2006 | 32 | 18 |
| 2005 | 32.76 | 19 |
| 2004 | 34.21 | 18 |
| 2003 | 42.71 | 7 |
| 2002 | 48.57 | 5 |
| 2001 | 33.75 | 22 |
| 2000 | 26.03 | 36 |
| 1999 | 35.31 | 22 |
| 1998 | 39.05 | 17 |
| 1997 | 34.03 | 27 |
| 1996 | 31.13 | 34 |
| 1995 | 32.06 | 33 |
| 1994 | 38.81 | 20 |
| 1993 | 33.9 | 29 |
| 1992 | 27.27 | 42 |
| 1991 | 31.22 | 33 |
| 1990 | 31.52 | 29 |
| 1989 | 32.16 | 25 |
| 1988 | 41.65 | 12 |
| 1987 | 37.26 | 15 |
| 1986 | 40.33 | 12 |