| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 1.98 | 27 |
| 2015 | 2.03 | 29 |
| 2014 | 2.08 | 29 |
| 2013 | 2.12 | 27 |
| 2012 | 2.16 | 26 |
| 2011 | 2.19 | 30 |
| 2010 | 2.22 | 29 |
| 2009 | 2.25 | 26 |
| 2008 | 2.26 | 28 |
| 2007 | 2.27 | 31 |
| 2006 | 2.27 | 31 |
| 2005 | 2.27 | 28 |
| 2004 | 2.27 | 32 |
| 2003 | 2.27 | 32 |
| 2002 | 2.28 | 35 |
| 2001 | 2.3 | 30 |
| 2000 | 2.31 | 30 |
| 1999 | 2.34 | 30 |
| 1998 | 2.38 | 28 |
| 1997 | 2.43 | 29 |
| 1996 | 2.5 | 27 |
| 1995 | 2.58 | 28 |
| 1994 | 2.66 | 26 |
| 1993 | 2.75 | 28 |
| 1992 | 2.83 | 23 |
| 1991 | 2.91 | 22 |
| 1990 | 3.03 | 15 |
| 1989 | 3.3 | 11 |
| 1988 | 3.38 | 11 |
| 1987 | 3.45 | 12 |
| 1986 | 3.51 | 10 |