| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.23 | 28 |
| 2015 | 3.87 | 37 |
| 2014 | 5.21 | 60 |
| 2013 | 1.63 | 11 |
| 2012 | 1.21 | 8 |
| 2011 | 0.89 | 6 |
| 2010 | 11.71 | 139 |
| 2009 | 6.15 | 66 |
| 2008 | 3 | 26 |
| 2007 | 1.71 | 11 |
| 2006 | 14.44 | 159 |
| 2005 | 7.04 | 80 |
| 2004 | 3.35 | 25 |
| 2003 | 3.78 | 30 |
| 2002 | 4.23 | 39 |
| 2001 | 0.97 | 5 |
| 2000 | 1.97 | 14 |
| 1999 | 5.11 | 48 |
| 1998 | 1.42 | 10 |
| 1997 | 1.62 | 11 |
| 1996 | 1.18 | 10 |
| 1995 | 0.79 | 4 |
| 1994 | 0.81 | 4 |
| 1993 | 2.74 | 22 |
| 1992 | 4.8 | 53 |
| 1991 | 8.49 | 104 |