| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 6.65 | 15 |
| 2015 | 6.49 | 22 |
| 2014 | 4.31 | 67 |
| 2013 | 3.49 | 91 |
| 2012 | 4.41 | 75 |
| 2011 | 1.76 | 147 |
| 2010 | 4.18 | 98 |
| 2009 | 2.42 | 68 |
| 2008 | 3.68 | 100 |
| 2007 | 4.94 | 118 |
| 2006 | 2.46 | 169 |
| 2005 | 5.62 | 84 |
| 2004 | 5.87 | 78 |
| 2003 | 6.68 | 50 |
| 2002 | 0.65 | 155 |
| 2001 | 4.58 | 56 |
| 2000 | 3.19 | 134 |
| 1999 | 6.36 | 37 |
| 1998 | 5.9 | 46 |
| 1997 | 3.12 | 129 |
| 1996 | 2.01 | 145 |
| 1995 | 5.36 | 65 |
| 1994 | -.02 | 150 |
| 1993 | 1.3 | 111 |
| 1992 | 1.24 | 99 |
| 1991 | 2.56 | 81 |
| 1990 | -.68 | 133 |
| 1989 | 3.98 | 79 |
| 1988 | -.59 | 144 |
| 1987 | 6.09 | 44 |
| 1986 | 3.11 | 89 |