| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 1.67 | 56 |
| 2015 | 1.72 | 61 |
| 2014 | 1.69 | 64 |
| 2013 | 1.61 | 64 |
| 2012 | 1.65 | 63 |
| 2011 | 1.93 | 46 |
| 2010 | 2.05 | 47 |
| 2009 | 2.14 | 48 |
| 2008 | 2.29 | 43 |
| 2007 | 2.5 | 37 |
| 2006 | 2.74 | 33 |
| 2005 | 2.85 | 28 |
| 2004 | 3.03 | 27 |
| 2003 | 3.34 | 27 |
| 2002 | 3.45 | 29 |
| 2001 | 3.14 | 32 |
| 2000 | 2.68 | 42 |
| 1999 | 2.7 | 43 |
| 1998 | 2.8 | 39 |
| 1997 | 2.89 | 40 |
| 1996 | 3.13 | 33 |
| 1995 | 3.24 | 32 |
| 1994 | 3.32 | 32 |
| 1993 | 3.3 | 34 |
| 1992 | 3.38 | 33 |
| 1991 | 3.8 | 31 |
| 1990 | 3.64 | 34 |
| 1989 | 3.97 | 30 |
| 1988 | 5.05 | 23 |
| 1987 | 6.52 | 12 |
| 1986 | 8.63 | 6 |