| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.53 | 127 |
| 2015 | 0.5 | 138 |
| 2014 | 0.51 | 142 |
| 2013 | 0.53 | 141 |
| 2012 | 0.54 | 141 |
| 2011 | 0.59 | 131 |
| 2010 | 0.67 | 129 |
| 2009 | 0.69 | 132 |
| 2008 | 0.62 | 138 |
| 2007 | 0.62 | 131 |
| 2006 | 0.66 | 132 |
| 2005 | 0.82 | 133 |
| 2004 | 0.67 | 139 |
| 2003 | 0.63 | 140 |
| 2002 | 0.61 | 136 |
| 2001 | 0.63 | 133 |
| 2000 | 0.59 | 135 |
| 1999 | 0.68 | 130 |
| 1998 | 0.74 | 127 |
| 1997 | 0.84 | 126 |
| 1996 | 0.93 | 119 |
| 1995 | 0.91 | 124 |
| 1994 | 0.93 | 121 |
| 1993 | 0.91 | 126 |
| 1992 | 0.88 | 117 |
| 1991 | 0.79 | 109 |
| 1990 | 0.83 | 110 |
| 1989 | 1.01 | 103 |
| 1988 | 1.11 | 102 |
| 1987 | 1.32 | 95 |
| 1986 | 1.15 | 95 |