| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 14.05 | 128 |
| 2015 | 13.56 | 127 |
| 2014 | 13.05 | 124 |
| 2013 | 12.52 | 124 |
| 2012 | 12.01 | 124 |
| 2011 | 11.54 | 124 |
| 2010 | 11.14 | 124 |
| 2009 | 10.84 | 123 |
| 2008 | 10.61 | 119 |
| 2007 | 10.43 | 117 |
| 2006 | 10.25 | 116 |
| 2005 | 10 | 114 |
| 2004 | 9.75 | 111 |
| 2003 | 9.44 | 110 |
| 2002 | 9.08 | 106 |
| 2001 | 8.71 | 102 |
| 2000 | 8.34 | 100 |
| 1999 | 8.11 | 97 |
| 1998 | 7.9 | 95 |
| 1997 | 7.69 | 92 |
| 1996 | 7.47 | 90 |
| 1995 | 7.22 | 83 |
| 1994 | 6.99 | 78 |
| 1993 | 6.75 | 70 |
| 1992 | 6.5 | 64 |
| 1991 | 6.25 | 58 |
| 1990 | 6 | 49 |
| 1989 | 5.81 | 43 |
| 1988 | 5.65 | 35 |
| 1987 | 5.53 | 30 |
| 1986 | 5.42 | 29 |