| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 11.76 | 114 |
| 2015 | 10.9 | 113 |
| 2014 | 10.2 | 106 |
| 2013 | 9.6 | 103 |
| 2012 | 9.11 | 98 |
| 2011 | 8.74 | 97 |
| 2010 | 8.47 | 94 |
| 2009 | 8.5 | 96 |
| 2008 | 8.65 | 97 |
| 2007 | 8.87 | 99 |
| 2006 | 9.11 | 101 |
| 2005 | 9.35 | 106 |
| 2004 | 9.54 | 109 |
| 2003 | 9.78 | 113 |
| 2002 | 10.04 | 120 |
| 2001 | 10.32 | 122 |
| 2000 | 10.59 | 128 |
| 1999 | 10.66 | 127 |
| 1998 | 10.69 | 127 |
| 1997 | 10.7 | 128 |
| 1996 | 10.69 | 128 |
| 1995 | 10.64 | 130 |
| 1994 | 10.49 | 129 |
| 1993 | 10.28 | 129 |
| 1992 | 10.05 | 126 |
| 1991 | 9.81 | 127 |
| 1990 | 9.6 | 129 |
| 1989 | 9.74 | 130 |
| 1988 | 9.94 | 131 |
| 1987 | 10.17 | 133 |
| 1986 | 10.42 | 135 |