| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.71 | 35 |
| 2015 | 3.5 | 32 |
| 2014 | 3.5 | 33 |
| 2013 | 2.89 | 20 |
| 2012 | 2.3 | 17 |
| 2011 | 2.7 | 16 |
| 2010 | 5.99 | 62 |
| 2009 | 3.4 | 25 |
| 2008 | 2.9 | 24 |
| 2007 | 5.2 | 60 |
| 2006 | 5.3 | 58 |
| 2005 | 5.4 | 58 |
| 2004 | 4.3 | 40 |
| 2003 | 5.45 | 53 |
| 2002 | 5.4 | 55 |
| 2001 | 5.4 | 57 |
| 2000 | 4.8 | 51 |
| 1999 | 4.33 | 37 |
| 1998 | 2.67 | 17 |
| 1997 | 2.08 | 14 |
| 1996 | 5.23 | 49 |
| 1995 | 3.69 | 38 |
| 1994 | 3.1 | 28 |
| 1993 | 6 | 71 |
| 1992 | 5.95 | 70 |
| 1991 | 5.9 | 72 |