| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 28.14 | 63 |
| 2015 | 27.74 | 77 |
| 2014 | 27.22 | 82 |
| 2013 | 25.85 | 96 |
| 2012 | 22.68 | 115 |
| 2011 | 21.15 | 127 |
| 2010 | 20.83 | 124 |
| 2009 | 21.01 | 120 |
| 2008 | 21.43 | 126 |
| 2007 | 19.22 | 140 |
| 2006 | 19.44 | 136 |
| 2005 | 19.49 | 134 |
| 2004 | 19.83 | 134 |
| 2003 | 19.74 | 138 |
| 2002 | 18.59 | 138 |
| 2001 | 19.79 | 131 |
| 2000 | 22.25 | 124 |
| 1999 | 23.38 | 114 |
| 1998 | 21.87 | 122 |
| 1997 | 22.15 | 118 |
| 1996 | 23.52 | 112 |
| 1995 | 23.56 | 111 |
| 1994 | 23.08 | 98 |
| 1993 | 23.65 | 95 |
| 1992 | 22.19 | 95 |
| 1991 | 22.27 | 95 |
| 1990 | 20.05 | 100 |
| 1989 | 21.34 | 82 |
| 1988 | 22.12 | 78 |
| 1987 | 25.08 | 69 |
| 1986 | 25.82 | 65 |