| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.88 | 112 |
| 2015 | 0.89 | 122 |
| 2014 | 0.78 | 128 |
| 2013 | 0.92 | 124 |
| 2012 | 0.71 | 133 |
| 2011 | 0.65 | 128 |
| 2010 | 0.62 | 134 |
| 2009 | 0.61 | 137 |
| 2008 | 0.63 | 137 |
| 2007 | 0.77 | 124 |
| 2006 | 0.72 | 129 |
| 2005 | 0.75 | 137 |
| 2004 | 0.95 | 125 |
| 2003 | 0.91 | 127 |
| 2002 | 0.7 | 131 |
| 2001 | 0.57 | 135 |
| 2000 | 0.68 | 130 |
| 1999 | 0.81 | 126 |
| 1998 | 1.02 | 113 |
| 1997 | 1.5 | 90 |
| 1996 | 1.26 | 101 |
| 1995 | 1.23 | 106 |
| 1994 | 1.27 | 111 |
| 1993 | 1.22 | 114 |
| 1992 | 1.47 | 99 |
| 1991 | 1.46 | 93 |
| 1990 | 1.52 | 90 |
| 1989 | 1.49 | 90 |
| 1988 | 1.61 | 87 |
| 1987 | 1.77 | 83 |
| 1986 | 2.17 | 66 |