| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.2 | 110 |
| 2015 | 5.1 | 107 |
| 2014 | 5.03 | 107 |
| 2013 | 4.98 | 107 |
| 2012 | 4.94 | 108 |
| 2011 | 4.9 | 109 |
| 2010 | 4.85 | 109 |
| 2009 | 4.88 | 106 |
| 2008 | 4.89 | 107 |
| 2007 | 4.87 | 107 |
| 2006 | 4.84 | 108 |
| 2005 | 4.79 | 109 |
| 2004 | 4.81 | 105 |
| 2003 | 4.82 | 102 |
| 2002 | 4.81 | 102 |
| 2001 | 4.77 | 102 |
| 2000 | 4.71 | 102 |
| 1999 | 4.6 | 103 |
| 1998 | 4.49 | 104 |
| 1997 | 4.38 | 105 |
| 1996 | 4.27 | 108 |
| 1995 | 4.15 | 108 |
| 1994 | 4.08 | 108 |
| 1993 | 4 | 110 |
| 1992 | 3.93 | 115 |
| 1991 | 3.86 | 115 |
| 1990 | 3.78 | 118 |
| 1989 | 3.75 | 119 |
| 1988 | 3.71 | 117 |
| 1987 | 3.69 | 117 |
| 1986 | 3.66 | 116 |