| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 4.04 | 55 |
| 2015 | 2.51 | 111 |
| 2014 | 3.16 | 99 |
| 2013 | 4.38 | 78 |
| 2012 | 2.38 | 116 |
| 2011 | 5.06 | 74 |
| 2010 | 5.52 | 74 |
| 2009 | 1.27 | 87 |
| 2008 | 3.06 | 121 |
| 2007 | 6.14 | 94 |
| 2006 | 5.8 | 87 |
| 2005 | 4.39 | 108 |
| 2004 | 5.11 | 97 |
| 2003 | 1.18 | 160 |
| 2002 | -.07 | 173 |
| 2001 | 0.24 | 168 |
| 2000 | 8.94 | 17 |
| 1999 | 3.74 | 84 |
| 1998 | 4.25 | 83 |
| 1997 | 4.08 | 104 |
| 1996 | 6.16 | 53 |
| 1995 | 6.6 | 43 |
| 1994 | 6.93 | 32 |
| 1993 | 5.56 | 46 |
| 1992 | 5.63 | 47 |
| 1991 | 7.7 | 23 |
| 1990 | 6.84 | 30 |
| 1989 | 0.87 | 126 |
| 1988 | 2.02 | 121 |
| 1987 | 7.19 | 34 |
| 1986 | 4.79 | 57 |