| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.98 | 48 |
| 2015 | 5.67 | 40 |
| 2014 | 5.4 | 33 |
| 2013 | 5.2 | 25 |
| 2012 | 5.04 | 19 |
| 2011 | 4.92 | 15 |
| 2010 | 4.82 | 14 |
| 2009 | 4.78 | 12 |
| 2008 | 4.7 | 11 |
| 2007 | 4.6 | 9 |
| 2006 | 4.46 | 7 |
| 2005 | 4.3 | 6 |
| 2004 | 4.14 | 6 |
| 2003 | 4.01 | 5 |
| 2002 | 3.88 | 5 |
| 2001 | 3.74 | 5 |
| 2000 | 3.58 | 4 |
| 1999 | 3.69 | 5 |
| 1998 | 3.8 | 5 |
| 1997 | 3.91 | 6 |
| 1996 | 4.02 | 7 |
| 1995 | 4.14 | 8 |
| 1994 | 4.13 | 6 |
| 1993 | 4.13 | 6 |
| 1992 | 4.16 | 6 |
| 1991 | 4.19 | 6 |
| 1990 | 4.21 | 6 |
| 1989 | 4.35 | 6 |
| 1988 | 4.46 | 6 |
| 1987 | 4.57 | 10 |
| 1986 | 4.68 | 10 |