| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.16 | 101 |
| 2015 | 7.73 | 106 |
| 2014 | 8.72 | 112 |
| 2013 | 8.78 | 113 |
| 2012 | 8.72 | 112 |
| 2011 | 5.68 | 63 |
| 2010 | 8.76 | 113 |
| 2009 | 4.12 | 35 |
| 2008 | 1.88 | 14 |
| 2007 | 8.78 | 124 |
| 2006 | 1.29 | 5 |
| 2005 | 4.79 | 48 |
| 2004 | 2.1 | 10 |
| 2003 | 3.84 | 32 |
| 2002 | 5.77 | 61 |
| 2001 | 4.96 | 51 |
| 2000 | 5.09 | 55 |
| 1999 | 8.88 | 105 |
| 1998 | 8.99 | 104 |
| 1997 | 9.1 | 104 |
| 1996 | 4.96 | 45 |
| 1995 | 5.45 | 57 |
| 1994 | 5.66 | 60 |
| 1993 | 2.44 | 18 |
| 1992 | 3.41 | 35 |
| 1991 | 2.1 | 18 |