| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.15 | 18 |
| 2015 | 2.2 | 21 |
| 2014 | 2.26 | 21 |
| 2013 | 2.3 | 20 |
| 2012 | 2.33 | 20 |
| 2011 | 2.35 | 24 |
| 2010 | 2.36 | 23 |
| 2009 | 2.38 | 20 |
| 2008 | 2.39 | 21 |
| 2007 | 2.4 | 23 |
| 2006 | 2.42 | 23 |
| 2005 | 2.42 | 20 |
| 2004 | 2.44 | 26 |
| 2003 | 2.45 | 28 |
| 2002 | 2.48 | 28 |
| 2001 | 2.53 | 24 |
| 2000 | 2.58 | 23 |
| 1999 | 2.64 | 24 |
| 1998 | 2.7 | 23 |
| 1997 | 2.75 | 22 |
| 1996 | 2.81 | 19 |
| 1995 | 2.86 | 18 |
| 1994 | 2.91 | 20 |
| 1993 | 2.96 | 22 |
| 1992 | 2.83 | 24 |
| 1991 | 2.25 | 43 |
| 1990 | 2.27 | 38 |
| 1989 | 2.3 | 42 |
| 1988 | 2.3 | 46 |
| 1987 | 2.29 | 49 |
| 1986 | 2.26 | 46 |