| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 12.28 | 107 |
| 2014 | 12.77 | 118 |
| 2013 | 11.56 | 138 |
| 2012 | 11.25 | 139 |
| 2011 | 10.84 | 145 |
| 2010 | 9.45 | 151 |
| 2009 | 9.99 | 145 |
| 2008 | 10.59 | 145 |
| 2007 | 12.11 | 137 |
| 2006 | 13.2 | 124 |
| 2005 | 14.02 | 112 |
| 2004 | 12.81 | 111 |
| 2003 | 12.61 | 111 |
| 2002 | 10.17 | 127 |
| 2001 | 8.98 | 133 |
| 2000 | 9.51 | 125 |
| 1999 | 9.11 | 124 |
| 1998 | 8.99 | 121 |
| 1997 | 9.37 | 115 |
| 1996 | 7.36 | 128 |
| 1995 | 8.08 | 121 |
| 1994 | 8.92 | 108 |
| 1993 | 8.77 | 107 |
| 1992 | 8.43 | 103 |
| 1991 | 8.76 | 94 |
| 1990 | 9.38 | 88 |
| 1989 | 9.36 | 83 |
| 1988 | 8.33 | 87 |
| 1987 | 9.24 | 83 |
| 1986 | 9.27 | 85 |