| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.92 | 5 |
| 2015 | 3.02 | 5 |
| 2014 | 3.12 | 7 |
| 2013 | 3.19 | 7 |
| 2012 | 3.23 | 8 |
| 2011 | 3.24 | 9 |
| 2010 | 3.22 | 9 |
| 2009 | 3.22 | 10 |
| 2008 | 3.23 | 10 |
| 2007 | 3.3 | 10 |
| 2006 | 3.42 | 9 |
| 2005 | 3.57 | 7 |
| 2004 | 3.7 | 7 |
| 2003 | 3.79 | 8 |
| 2002 | 3.79 | 7 |
| 2001 | 3.73 | 6 |
| 2000 | 3.63 | 8 |
| 1999 | 3.54 | 11 |
| 1998 | 3.45 | 10 |
| 1997 | 3.38 | 13 |
| 1996 | 3.33 | 11 |
| 1995 | 3.28 | 13 |
| 1994 | 3.21 | 12 |
| 1993 | 2.98 | 20 |
| 1992 | 2.92 | 19 |
| 1991 | 2.92 | 21 |
| 1990 | 2.96 | 18 |
| 1989 | 2.98 | 15 |
| 1988 | 2.95 | 20 |
| 1987 | 2.84 | 26 |
| 1986 | 2.68 | 33 |