| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.85 | 76 |
| 2015 | 1.79 | 84 |
| 2014 | 0.19 | 147 |
| 2013 | 1.77 | 119 |
| 2012 | 2.63 | 126 |
| 2011 | 3.57 | 119 |
| 2010 | 1.83 | 130 |
| 2009 | 3.31 | 86 |
| 2008 | 8.68 | 94 |
| 2007 | 0.96 | 165 |
| 2006 | 2.23 | 142 |
| 2005 | 6.8 | 65 |
| 2004 | 0.39 | 156 |
| 2003 | -.96 | 163 |
| 2002 | 3.07 | 86 |
| 2001 | 3.91 | 87 |
| 2000 | 1.89 | 118 |
| 1999 | -.07 | 146 |
| 1998 | 0.97 | 137 |
| 1997 | 8.25 | 60 |
| 1996 | 4.69 | 102 |
| 1995 | 16.43 | 53 |
| 1994 | 39.16 | 30 |
| 1993 | -1.01 | 148 |
| 1992 | 1.39 | 126 |
| 1991 | 0.39 | 131 |
| 1990 | 1.02 | 125 |
| 1989 | -.84 | 130 |
| 1988 | -.15 | 126 |
| 1987 | 0.05 | 114 |
| 1986 | 4.12 | 77 |