| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 9.62 | 121 |
| 2014 | 9.51 | 133 |
| 2013 | 11.01 | 142 |
| 2012 | 8.99 | 151 |
| 2011 | 10.66 | 147 |
| 2010 | 10.86 | 141 |
| 2009 | 9.14 | 151 |
| 2008 | 9.36 | 147 |
| 2007 | 7.62 | 154 |
| 2006 | 7.56 | 152 |
| 2005 | 8.89 | 148 |
| 2004 | 8.88 | 139 |
| 2003 | 7.7 | 142 |
| 2002 | 11.66 | 117 |
| 2001 | 11.09 | 119 |
| 2000 | 12.63 | 104 |
| 1999 | 22.38 | 48 |
| 1998 | 36.95 | 25 |
| 1997 | 25.27 | 38 |
| 1996 | 12.01 | 92 |
| 1995 | 13.22 | 82 |
| 1994 | 17.14 | 67 |
| 1993 | 14.16 | 77 |
| 1992 | 8.01 | 109 |
| 1991 | 8.31 | 99 |
| 1990 | 5.79 | 113 |
| 1989 | 6.76 | 107 |
| 1988 | 7.43 | 99 |
| 1987 | 5.92 | 105 |
| 1986 | 3.28 | 114 |