| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.53 | 35 |
| 2015 | 5.46 | 33 |
| 2014 | 5.48 | 34 |
| 2013 | 5.57 | 35 |
| 2012 | 5.71 | 39 |
| 2011 | 5.86 | 42 |
| 2010 | 5.98 | 50 |
| 2009 | 6.08 | 52 |
| 2008 | 6.13 | 56 |
| 2007 | 6.15 | 57 |
| 2006 | 6.16 | 61 |
| 2005 | 6.18 | 62 |
| 2004 | 6.23 | 64 |
| 2003 | 6.29 | 62 |
| 2002 | 6.36 | 61 |
| 2001 | 6.42 | 61 |
| 2000 | 6.47 | 62 |
| 1999 | 6.55 | 65 |
| 1998 | 6.63 | 65 |
| 1997 | 6.71 | 68 |
| 1996 | 6.79 | 74 |
| 1995 | 6.89 | 78 |
| 1994 | 7.01 | 79 |
| 1993 | 7.15 | 85 |
| 1992 | 7.3 | 88 |
| 1991 | 7.45 | 95 |
| 1990 | 7.59 | 101 |
| 1989 | 7.72 | 109 |
| 1988 | 7.84 | 112 |
| 1987 | 7.94 | 113 |
| 1986 | 8.02 | 114 |