| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 10.19 | 66 |
| 2014 | 6.9 | 106 |
| 2013 | 13.73 | 58 |
| 2012 | 5.99 | 113 |
| 2011 | 11.61 | 76 |
| 2010 | 8.72 | 108 |
| 2009 | 59.59 | 2 |
| 2008 | 13.3 | 93 |
| 2007 | 16.14 | 98 |
| 2006 | 29.68 | 35 |
| 2005 | 5.11 | 146 |
| 2004 | 22.52 | 37 |
| 2003 | 2.09 | 141 |
| 2002 | 15.36 | 61 |
| 2001 | 6.17 | 122 |
| 2000 | 13.2 | 78 |
| 1999 | 19.5 | 47 |
| 1998 | 10.55 | 85 |
| 1997 | 8.09 | 116 |
| 1996 | 24.08 | 47 |
| 1995 | 22.59 | 53 |
| 1994 | 30.93 | 53 |
| 1993 | 19.41 | 64 |
| 1992 | 46.57 | 22 |
| 1991 | 30.3 | 33 |