| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 10.7 | 107 |
| 2015 | 10.43 | 106 |
| 2014 | 10.2 | 107 |
| 2013 | 10.02 | 107 |
| 2012 | 9.89 | 106 |
| 2011 | 9.78 | 107 |
| 2010 | 9.66 | 107 |
| 2009 | 9.52 | 107 |
| 2008 | 9.37 | 104 |
| 2007 | 9.23 | 101 |
| 2006 | 9.09 | 100 |
| 2005 | 8.97 | 100 |
| 2004 | 8.82 | 99 |
| 2003 | 8.68 | 99 |
| 2002 | 8.55 | 99 |
| 2001 | 8.42 | 100 |
| 2000 | 8.29 | 98 |
| 1999 | 8.17 | 98 |
| 1998 | 8.05 | 98 |
| 1997 | 7.93 | 98 |
| 1996 | 7.81 | 96 |
| 1995 | 7.69 | 95 |
| 1994 | 7.62 | 96 |
| 1993 | 7.55 | 93 |
| 1992 | 7.49 | 94 |
| 1991 | 7.43 | 94 |
| 1990 | 7.37 | 92 |
| 1989 | 7.36 | 92 |
| 1988 | 7.36 | 93 |
| 1987 | 7.37 | 96 |
| 1986 | 7.38 | 98 |