| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 9.19 | 72 |
| 2015 | 8.9 | 72 |
| 2014 | 8.6 | 71 |
| 2013 | 8.29 | 71 |
| 2012 | 7.99 | 72 |
| 2011 | 7.71 | 72 |
| 2010 | 7.46 | 73 |
| 2009 | 7.22 | 74 |
| 2008 | 7.01 | 76 |
| 2007 | 6.82 | 79 |
| 2006 | 6.65 | 80 |
| 2005 | 6.48 | 82 |
| 2004 | 6.3 | 82 |
| 2003 | 6.14 | 82 |
| 2002 | 5.98 | 82 |
| 2001 | 5.83 | 82 |
| 2000 | 5.7 | 84 |
| 1999 | 5.57 | 84 |
| 1998 | 5.46 | 85 |
| 1997 | 5.36 | 85 |
| 1996 | 5.26 | 84 |
| 1995 | 5.16 | 83 |
| 1994 | 5.06 | 83 |
| 1993 | 4.96 | 83 |
| 1992 | 4.87 | 84 |
| 1991 | 4.78 | 82 |
| 1990 | 4.7 | 82 |
| 1989 | 4.61 | 82 |
| 1988 | 4.53 | 82 |
| 1987 | 4.46 | 84 |
| 1986 | 4.39 | 85 |