| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.2 | 37 |
| 2015 | 2.34 | 40 |
| 2014 | 2.32 | 39 |
| 2013 | 2.34 | 38 |
| 2012 | 2.26 | 37 |
| 2011 | 1.64 | 59 |
| 2010 | 0.98 | 112 |
| 2006 | 2.97 | 28 |
| 2005 | 2.28 | 47 |
| 2004 | 4.41 | 14 |
| 2003 | 3.4 | 26 |
| 2002 | 10.67 | 3 |
| 2001 | 4.23 | 18 |
| 2000 | 5.18 | 12 |
| 1999 | 3.84 | 25 |
| 1998 | 4.78 | 19 |
| 1997 | 3.65 | 30 |
| 1996 | 3.41 | 26 |
| 1995 | 3.7 | 24 |
| 1994 | 3.6 | 29 |
| 1993 | 3.81 | 30 |
| 1992 | 4.39 | 22 |
| 1991 | 4.35 | 27 |
| 1990 | 4.74 | 22 |
| 1989 | 4.93 | 20 |
| 1988 | 5.21 | 21 |
| 1987 | 5.82 | 16 |
| 1986 | 5.5 | 14 |