| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.19 | 95 |
| 2015 | -.9 | 158 |
| 2014 | 1.89 | 102 |
| 2013 | 2.18 | 105 |
| 2012 | 3.02 | 110 |
| 2011 | 3.81 | 117 |
| 2010 | 3.25 | 97 |
| 2009 | -.85 | 168 |
| 2008 | 5.47 | 129 |
| 2007 | 2.24 | 145 |
| 2006 | 4.64 | 87 |
| 2005 | 4.54 | 85 |
| 2004 | 2.76 | 106 |
| 2003 | 1.8 | 122 |
| 2002 | 0.7 | 146 |
| 2001 | 1.63 | 139 |
| 2000 | 1.59 | 124 |
| 1999 | 0.28 | 142 |
| 1998 | 7.99 | 57 |
| 1997 | 5.63 | 81 |
| 1996 | 5.81 | 93 |
| 1995 | 5.82 | 107 |
| 1994 | 5.05 | 105 |
| 1993 | 3.31 | 109 |
| 1992 | 4.14 | 95 |
| 1991 | 5.71 | 93 |
| 1990 | 5.86 | 89 |
| 1989 | 5.36 | 87 |
| 1988 | 3.86 | 94 |
| 1987 | 2.47 | 99 |
| 1986 | 1.84 | 94 |