| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 4.59 | 12 |
| 2014 | 4.42 | 11 |
| 2013 | 4.1 | 12 |
| 2012 | 3.84 | 13 |
| 2011 | 3.54 | 15 |
| 2010 | 3.28 | 24 |
| 2009 | 3.61 | 22 |
| 2008 | 2.8 | 32 |
| 2007 | 2.96 | 27 |
| 2006 | 3.1 | 26 |
| 2005 | 3.21 | 22 |
| 2004 | 4.04 | 17 |
| 2003 | 4.66 | 14 |
| 2002 | 4.61 | 15 |
| 2001 | 4.15 | 20 |
| 2000 | 3.96 | 22 |
| 1999 | 5.5 | 12 |
| 1998 | 5.33 | 14 |
| 1997 | 5.07 | 16 |
| 1996 | 5.27 | 16 |
| 1995 | 5.18 | 15 |
| 1994 | 5.11 | 16 |
| 1993 | 5.37 | 16 |
| 1992 | 5.88 | 16 |
| 1991 | 5.7 | 17 |
| 1990 | 5.66 | 20 |
| 1989 | 5.64 | 16 |
| 1988 | 5.6 | 18 |