| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.71 | 86 |
| 2015 | 0.76 | 87 |
| 2014 | 0.82 | 85 |
| 2013 | 0.83 | 84 |
| 2012 | 0.82 | 84 |
| 2011 | 0.78 | 89 |
| 2010 | 0.73 | 91 |
| 2009 | 0.7 | 98 |
| 2008 | 0.68 | 101 |
| 2007 | 0.71 | 101 |
| 2006 | 0.76 | 96 |
| 2005 | 0.8 | 94 |
| 2004 | 0.87 | 92 |
| 2003 | 0.95 | 86 |
| 2002 | 1.09 | 80 |
| 2001 | 1.35 | 68 |
| 2000 | 1.68 | 52 |
| 1999 | 1.83 | 46 |
| 1998 | 1.96 | 48 |
| 1997 | 1.98 | 49 |
| 1996 | 1.81 | 54 |
| 1995 | 1.63 | 62 |
| 1994 | 1.58 | 66 |
| 1993 | 1.52 | 71 |
| 1992 | 1.43 | 74 |
| 1991 | 1.38 | 75 |
| 1990 | 1.35 | 78 |
| 1989 | 1.27 | 91 |
| 1988 | 1.22 | 90 |
| 1987 | 1.17 | 94 |
| 1986 | 1.14 | 92 |