| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 8.37 | 13 |
| 2015 | 6.45 | 38 |
| 2014 | 7.76 | 28 |
| 2013 | 9.24 | 26 |
| 2012 | 7.26 | 36 |
| 2011 | 1.85 | 125 |
| 2010 | 11.58 | 27 |
| 2009 | -1.92 | 86 |
| 2008 | 4.81 | 68 |
| 2007 | 5.77 | 85 |
| 2006 | 4.61 | 92 |
| 2005 | 4.19 | 87 |
| 2004 | 5.23 | 78 |
| 2003 | 4.28 | 81 |
| 2002 | 2.89 | 92 |
| 2001 | 0.96 | 107 |
| 2000 | 6.55 | 55 |
| 1999 | -1.48 | 133 |
| 1998 | -2.12 | 144 |
| 1997 | 6.14 | 59 |
| 1996 | 6.44 | 46 |
| 1995 | 6.72 | 42 |
| 1994 | 5.77 | 47 |
| 1993 | 1.65 | 65 |
| 1992 | -.54 | 87 |
| 1991 | -2.67 | 97 |
| 1990 | 2.56 | 57 |
| 1989 | 7.38 | 34 |
| 1988 | 8.75 | 30 |
| 1987 | 4.01 | 56 |
| 1986 | 2.3 | 66 |