| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.57 | 95 |
| 2015 | 0.22 | 116 |
| 2014 | -.08 | 135 |
| 2013 | -.19 | 142 |
| 2012 | -.05 | 134 |
| 2011 | 0.28 | 115 |
| 2010 | 0.69 | 93 |
| 2009 | 1.07 | 79 |
| 2008 | 1.37 | 68 |
| 2007 | 1.53 | 60 |
| 2006 | 1.58 | 57 |
| 2005 | 1.62 | 55 |
| 2004 | 1.69 | 53 |
| 2003 | 1.75 | 51 |
| 2002 | 1.82 | 46 |
| 2001 | 1.91 | 43 |
| 2000 | 1.98 | 41 |
| 1999 | 2.04 | 42 |
| 1998 | 2.12 | 41 |
| 1997 | 2.21 | 41 |
| 1996 | 2.32 | 37 |
| 1995 | 2.44 | 34 |
| 1994 | 2.55 | 30 |
| 1993 | 2.59 | 32 |
| 1992 | 2.53 | 35 |
| 1991 | 2.39 | 39 |
| 1990 | 2.18 | 43 |
| 1989 | 1.81 | 62 |
| 1988 | 1.51 | 76 |
| 1987 | 1.61 | 73 |
| 1986 | 1.83 | 65 |