| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.44 | 17 |
| 2015 | 2.78 | 21 |
| 2014 | 3.42 | 30 |
| 2013 | 3.49 | 33 |
| 2012 | 3.55 | 33 |
| 2011 | 3.6 | 33 |
| 2010 | 1.8 | 11 |
| 2009 | 1.6 | 9 |
| 2008 | 1.8 | 12 |
| 2007 | 1.5 | 9 |
| 2006 | 1.3 | 6 |
| 2005 | 1.95 | 12 |
| 2004 | 1.7 | 7 |
| 2003 | 1.3 | 5 |
| 2002 | 1.1 | 6 |
| 2001 | 0.8 | 3 |
| 2000 | 0.8 | 3 |
| 1999 | 0.7 | 3 |
| 1998 | 0.7 | 2 |
| 1997 | 0.7 | 2 |
| 1996 | 0.7 | 4 |
| 1995 | 2.13 | 17 |
| 1994 | 0.7 | 3 |
| 1993 | 0.8 | 4 |
| 1992 | 0.88 | 4 |
| 1991 | 0.93 | 7 |