| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.56 | 71 |
| 2015 | 2.63 | 72 |
| 2014 | 2.7 | 68 |
| 2013 | 2.39 | 80 |
| 2012 | 2.84 | 68 |
| 2011 | 2.52 | 78 |
| 2010 | 2.99 | 68 |
| 2009 | 2.22 | 91 |
| 2008 | 2.68 | 76 |
| 2007 | 2.3 | 83 |
| 2006 | 2.76 | 76 |
| 2005 | 2.3 | 90 |
| 2004 | 1.94 | 102 |
| 2003 | 2.19 | 92 |
| 2002 | 2.52 | 83 |
| 2001 | 2.53 | 88 |
| 2000 | 2.54 | 83 |
| 1999 | 2.54 | 82 |
| 1998 | 2.55 | 82 |
| 1997 | 2.59 | 84 |
| 1996 | 2.1 | 104 |
| 1995 | 2.45 | 93 |
| 1994 | 2.85 | 82 |
| 1993 | 2.76 | 86 |
| 1992 | 2.68 | 92 |
| 1991 | 2.76 | 98 |
| 1990 | 2.55 | 103 |
| 1989 | 2.2 | 120 |
| 1988 | 2.2 | 125 |
| 1987 | 2.24 | 125 |
| 1986 | 2.12 | 130 |