| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 8.32 | 89 |
| 2015 | 8.19 | 89 |
| 2014 | 8.09 | 89 |
| 2013 | 7.95 | 89 |
| 2012 | 7.8 | 87 |
| 2011 | 7.66 | 89 |
| 2010 | 7.56 | 87 |
| 2009 | 7.55 | 87 |
| 2008 | 7.6 | 85 |
| 2007 | 7.7 | 85 |
| 2006 | 7.8 | 88 |
| 2005 | 7.89 | 92 |
| 2004 | 8.02 | 93 |
| 2003 | 8.13 | 93 |
| 2002 | 8.23 | 94 |
| 2001 | 8.32 | 97 |
| 2000 | 8.38 | 101 |
| 1999 | 8.46 | 103 |
| 1998 | 8.51 | 104 |
| 1997 | 8.53 | 107 |
| 1996 | 8.54 | 110 |
| 1995 | 8.52 | 112 |
| 1994 | 8.5 | 113 |
| 1993 | 8.47 | 114 |
| 1992 | 8.41 | 115 |
| 1991 | 8.35 | 117 |
| 1990 | 8.27 | 117 |
| 1989 | 8.25 | 116 |
| 1988 | 8.23 | 117 |
| 1987 | 8.22 | 118 |
| 1986 | 8.21 | 119 |