| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 38.85 | 98 |
| 2015 | 37.87 | 116 |
| 2014 | 34.14 | 119 |
| 2013 | 31.98 | 124 |
| 2012 | 29.83 | 127 |
| 2011 | 29.08 | 127 |
| 2010 | 28.94 | 130 |
| 2009 | 27.52 | 131 |
| 2008 | 23.56 | 136 |
| 2007 | 21.43 | 144 |
| 2006 | 21.07 | 140 |
| 2005 | 20.27 | 135 |
| 2004 | 23.42 | 124 |
| 2003 | 25.52 | 119 |
| 2002 | 16.52 | 142 |
| 2001 | 18.45 | 134 |
| 2000 | 20.95 | 120 |
| 1999 | 19.68 | 123 |
| 1998 | 21.53 | 111 |
| 1997 | 24.68 | 100 |
| 1996 | 22.63 | 107 |
| 1995 | 23.97 | 102 |
| 1994 | 22.13 | 112 |
| 1993 | 19.87 | 118 |
| 1992 | 18.76 | 118 |
| 1991 | 18.13 | 115 |
| 1990 | 18.18 | 112 |
| 1989 | 18.49 | 106 |
| 1988 | 19.08 | 104 |
| 1987 | 17.9 | 105 |
| 1986 | 16.19 | 108 |