| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 14.4 | 125 |
| 2015 | 15.27 | 146 |
| 2014 | 15.58 | 151 |
| 2013 | 16.93 | 148 |
| 2012 | 17.4 | 144 |
| 2011 | 19.34 | 136 |
| 2010 | 20.1 | 134 |
| 2009 | 20.27 | 125 |
| 2008 | 22.04 | 122 |
| 2007 | 21.23 | 126 |
| 2006 | 22.38 | 119 |
| 2005 | 23.5 | 116 |
| 2004 | 24.95 | 109 |
| 2003 | 27.57 | 84 |
| 2002 | 27.49 | 84 |
| 2001 | 26.6 | 93 |
| 2000 | 29.89 | 71 |
| 1999 | 27.36 | 84 |
| 1998 | 28.36 | 79 |
| 1997 | 28.26 | 84 |
| 1996 | 28.48 | 86 |
| 1995 | 29.22 | 79 |
| 1994 | 51.28 | 4 |
| 1993 | 49.89 | 7 |
| 1992 | 51.58 | 7 |
| 1991 | 55.22 | 5 |
| 1990 | 55.85 | 5 |
| 1989 | 57.36 | 5 |
| 1988 | 57.09 | 4 |
| 1987 | 57.77 | 5 |
| 1986 | 59.84 | 4 |