| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 7.31 | 131 |
| 2014 | 6.62 | 145 |
| 2013 | 6.35 | 161 |
| 2012 | 5.98 | 164 |
| 2011 | 5.87 | 170 |
| 2010 | 6.32 | 164 |
| 2009 | 6.83 | 161 |
| 2008 | 7.47 | 155 |
| 2007 | 7.03 | 159 |
| 2006 | 6.43 | 161 |
| 2005 | 6.79 | 159 |
| 2004 | 6.76 | 147 |
| 2003 | 7.07 | 144 |
| 2002 | 6.67 | 144 |
| 2001 | 6.8 | 138 |
| 2000 | 6.85 | 134 |
| 1999 | 7.17 | 132 |
| 1998 | 7.04 | 129 |
| 1997 | 6.28 | 132 |
| 1996 | 6.04 | 132 |
| 1995 | 5.08 | 134 |
| 1994 | 5.4 | 125 |
| 1993 | 5.82 | 123 |
| 1992 | 5.99 | 118 |
| 1991 | 5.88 | 115 |
| 1990 | 7.35 | 106 |
| 1989 | 9.03 | 87 |
| 1988 | 13 | 63 |
| 1987 | 9.45 | 82 |
| 1986 | 11.11 | 67 |