| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.25 | 94 |
| 2015 | 0.45 | 123 |
| 2014 | 0.56 | 131 |
| 2013 | 0.79 | 153 |
| 2012 | 2.4 | 137 |
| 2011 | 2.76 | 151 |
| 2010 | 2.3 | 120 |
| 2009 | 1.33 | 123 |
| 2008 | 3.4 | 162 |
| 2007 | 1.71 | 157 |
| 2006 | 1.89 | 156 |
| 2005 | 1.81 | 147 |
| 2004 | 1.16 | 143 |
| 2003 | 2.09 | 115 |
| 2002 | 2.43 | 104 |
| 2001 | 2.35 | 124 |
| 2000 | 2.92 | 97 |
| 1999 | 2.48 | 95 |
| 1998 | 1.85 | 122 |
| 1997 | 2.2 | 124 |
| 1996 | 2.11 | 132 |
| 1995 | 2.1 | 139 |
| 1994 | 1.99 | 133 |
| 1993 | 1.25 | 134 |
| 1992 | 2.1 | 120 |
| 1991 | 2.37 | 122 |
| 1990 | 2.65 | 119 |
| 1989 | 4.78 | 92 |
| 1988 | 4.55 | 84 |
| 1987 | 3.99 | 83 |
| 1986 | 3.72 | 79 |