| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 11.16 | 137 |
| 2015 | 12.44 | 147 |
| 2014 | 13.89 | 151 |
| 2013 | 16.18 | 160 |
| 2012 | 15.53 | 160 |
| 2011 | 12.68 | 139 |
| 2010 | 10.77 | 132 |
| 2009 | 9.43 | 126 |
| 2008 | 7.55 | 111 |
| 2007 | 7.96 | 110 |
| 2006 | 7.65 | 102 |
| 2005 | 7.58 | 92 |
| 2004 | 6.32 | 67 |
| 2003 | 6.13 | 65 |
| 2002 | 4.5 | 44 |
| 2001 | 3.83 | 36 |
| 2000 | 3.82 | 35 |
| 1999 | 4.59 | 40 |
| 1998 | 4.65 | 46 |
| 1997 | 6.57 | 68 |
| 1996 | 7.3 | 85 |
| 1995 | 7.06 | 82 |
| 1994 | 6.71 | 75 |
| 1993 | 5.3 | 59 |
| 1992 | 3.98 | 45 |
| 1991 | 3.92 | 47 |