| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 6.11 | 79 |
| 2015 | 5.72 | 71 |
| 2014 | 5.62 | 66 |
| 2013 | 5.34 | 63 |
| 2012 | 4.86 | 51 |
| 2011 | 4.56 | 50 |
| 2010 | 4.82 | 46 |
| 2009 | 5.3 | 51 |
| 2008 | 4.13 | 47 |
| 2007 | 4.86 | 55 |
| 2006 | 5.24 | 56 |
| 2005 | 5.63 | 63 |
| 2004 | 5.83 | 62 |
| 2003 | 4.78 | 46 |
| 2002 | 4.85 | 46 |
| 2001 | 4.01 | 39 |
| 2000 | 4.69 | 48 |
| 1999 | 4.7 | 42 |
| 1998 | 5.52 | 57 |
| 1997 | 5.15 | 52 |
| 1996 | 5.28 | 51 |
| 1995 | 4.35 | 43 |
| 1994 | 3.54 | 33 |
| 1993 | 4.3 | 47 |
| 1992 | 3.6 | 37 |
| 1991 | 3.4 | 40 |