| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 5.31 | 58 |
| 2014 | 3.29 | 85 |
| 2013 | 5.34 | 48 |
| 2012 | 8.17 | 38 |
| 2011 | 7.46 | 45 |
| 2010 | 9.28 | 30 |
| 2009 | 15.13 | 11 |
| 2008 | 12.05 | 27 |
| 2007 | 10.75 | 37 |
| 2006 | 5.34 | 77 |
| 2005 | 1.7 | 134 |
| 2004 | 1.21 | 137 |
| 2003 | 0.24 | 170 |
| 2002 | 0.33 | 156 |
| 2001 | 2.05 | 98 |
| 2000 | 2.14 | 105 |
| 1999 | 1.57 | 108 |
| 1998 | 0.44 | 146 |
| 1997 | 0.39 | 151 |
| 1996 | 0.25 | 148 |
| 1995 | 0.31 | 140 |
| 1994 | 0.19 | 128 |
| 1993 | 0.46 | 107 |
| 1992 | 0.7 | 79 |
| 1991 | 0.52 | 87 |
| 1990 | 0.73 | 79 |
| 1989 | 0.51 | 76 |
| 1988 | 0.12 | 102 |
| 1987 | 0.14 | 97 |
| 1986 | 0.43 | 73 |