| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.94 | 6 |
| 2015 | 6.13 | 10 |
| 2014 | 5.99 | 14 |
| 2013 | 6.33 | 15 |
| 2012 | 6.62 | 19 |
| 2011 | 5.43 | 36 |
| 2010 | 5.48 | 35 |
| 2009 | 6.29 | 9 |
| 2008 | 7.26 | 22 |
| 2007 | 8.37 | 31 |
| 2006 | 6 | 56 |
| 2005 | 5.76 | 44 |
| 2004 | 6.46 | 42 |
| 2003 | 2.99 | 84 |
| 2002 | 2.73 | 71 |
| 2001 | 2.89 | 65 |
| 2000 | 2.37 | 120 |
| 1999 | 3.18 | 70 |
| 1998 | 2.63 | 95 |
| 1997 | 3.24 | 80 |
| 1996 | -.23 | 159 |
| 1995 | -2.67 | 163 |
| 1994 | -7.04 | 165 |
| 1993 | -4.5 | 156 |
| 1992 | -13.26 | 167 |
| 1991 | -2.59 | 130 |
| 1990 | -1.03 | 113 |
| 1989 | 0.63 | 103 |
| 1988 | 6.5 | 32 |