| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.46 | 41 |
| 2015 | 4.17 | 24 |
| 2014 | 4.88 | 14 |
| 2013 | 5.42 | 11 |
| 2012 | 5.66 | 7 |
| 2011 | 5.63 | 7 |
| 2010 | 5.47 | 11 |
| 2009 | 5.29 | 12 |
| 2008 | 5 | 17 |
| 2007 | 4.59 | 24 |
| 2006 | 4.11 | 32 |
| 2005 | 3.5 | 51 |
| 2004 | 2.88 | 71 |
| 2003 | 2.39 | 83 |
| 2002 | 2.14 | 100 |
| 2001 | 2.1 | 103 |
| 2000 | 2.1 | 97 |
| 1999 | 2.11 | 96 |
| 1998 | 2.32 | 94 |
| 1997 | 2.8 | 76 |
| 1996 | 3.46 | 62 |
| 1995 | 4.75 | 19 |
| 1994 | 6.18 | 7 |
| 1993 | 6.86 | 7 |
| 1992 | 7.07 | 6 |
| 1991 | 6.85 | 7 |
| 1990 | 6.41 | 12 |
| 1989 | 6 | 17 |
| 1988 | 5.71 | 23 |
| 1987 | 5.67 | 26 |
| 1986 | 5.85 | 29 |