| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.9 | 70 |
| 2015 | 5.9 | 137 |
| 2014 | 6.22 | 149 |
| 2013 | 5.6 | 167 |
| 2012 | 5.64 | 168 |
| 2011 | 5.93 | 169 |
| 2010 | 4.24 | 172 |
| 2009 | 5.26 | 170 |
| 2008 | 6.56 | 161 |
| 2007 | 7.17 | 157 |
| 2006 | 7.08 | 156 |
| 2005 | 7.11 | 156 |
| 2004 | 7.78 | 144 |
| 2003 | 6.82 | 145 |
| 2002 | 10.13 | 128 |
| 2001 | 9.67 | 128 |
| 2000 | 9.49 | 127 |
| 1999 | 8.98 | 126 |
| 1998 | 8.71 | 124 |
| 1997 | 8.93 | 124 |
| 1996 | 5 | 135 |
| 1995 | 6.04 | 131 |
| 1994 | 5.83 | 123 |
| 1993 | 5.22 | 126 |
| 1992 | 4.38 | 122 |
| 1991 | 2.9 | 127 |
| 1990 | 2.83 | 126 |
| 1989 | 2.45 | 123 |
| 1988 | 2.71 | 119 |
| 1987 | 2.54 | 118 |
| 1986 | 2.03 | 118 |