| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.39 | 75 |
| 2015 | 7.07 | 74 |
| 2014 | 6.86 | 70 |
| 2013 | 6.7 | 70 |
| 2012 | 6.59 | 69 |
| 2011 | 6.53 | 67 |
| 2010 | 6.49 | 67 |
| 2009 | 6.55 | 69 |
| 2008 | 6.65 | 69 |
| 2007 | 6.76 | 70 |
| 2006 | 6.89 | 72 |
| 2005 | 7 | 76 |
| 2004 | 6.99 | 74 |
| 2003 | 6.95 | 74 |
| 2002 | 6.9 | 74 |
| 2001 | 6.79 | 72 |
| 2000 | 6.65 | 69 |
| 1999 | 6.81 | 74 |
| 1998 | 6.85 | 75 |
| 1997 | 6.8 | 75 |
| 1996 | 6.72 | 70 |
| 1995 | 6.67 | 69 |
| 1994 | 6.71 | 69 |
| 1993 | 6.8 | 72 |
| 1992 | 6.87 | 75 |
| 1991 | 6.88 | 79 |
| 1990 | 6.83 | 79 |
| 1989 | 6.89 | 83 |
| 1988 | 6.94 | 86 |
| 1987 | 6.98 | 86 |
| 1986 | 7.02 | 87 |