| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 10.12 | 64 |
| 2015 | 9.68 | 66 |
| 2014 | 9.31 | 66 |
| 2013 | 9.02 | 66 |
| 2012 | 8.79 | 66 |
| 2011 | 8.59 | 66 |
| 2010 | 8.4 | 67 |
| 2009 | 8.23 | 67 |
| 2008 | 8.09 | 66 |
| 2007 | 7.96 | 65 |
| 2006 | 7.83 | 64 |
| 2005 | 7.69 | 64 |
| 2004 | 7.55 | 65 |
| 2003 | 7.4 | 67 |
| 2002 | 7.23 | 67 |
| 2001 | 7.07 | 68 |
| 2000 | 6.91 | 69 |
| 1999 | 6.76 | 71 |
| 1998 | 6.62 | 71 |
| 1997 | 6.48 | 70 |
| 1996 | 6.33 | 70 |
| 1995 | 6.16 | 70 |
| 1994 | 6.04 | 70 |
| 1993 | 5.93 | 72 |
| 1992 | 5.82 | 72 |
| 1991 | 5.72 | 72 |
| 1990 | 5.65 | 70 |
| 1989 | 5.58 | 69 |
| 1988 | 5.53 | 69 |
| 1987 | 5.47 | 68 |
| 1986 | 5.41 | 68 |