| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 5.161 | 117 |
| 2014 | 5.868 | 110 |
| 2013 | 5.935 | 113 |
| 2012 | 6.035 | 114 |
| 2011 | 6.791 | 107 |
| 2010 | 7.248 | 111 |
| 2009 | 7.941 | 108 |
| 2008 | 8.223 | 109 |
| 2007 | 8.266 | 112 |
| 2006 | 7.975 | 115 |
| 2005 | 7.822 | 108 |
| 2004 | 7.904 | 109 |
| 2003 | 8.295 | 106 |
| 2002 | 8.407 | 111 |
| 2001 | 10.692 | 100 |
| 2000 | 11.603 | 95 |
| 1999 | 11.734 | 99 |
| 1998 | 11.796 | 99 |
| 1997 | 12.197 | 91 |
| 1996 | 12.32 | 93 |
| 1995 | 11.702 | 92 |
| 1994 | 10.712 | 89 |
| 1993 | 10.836 | 88 |
| 1992 | 11.727 | 80 |
| 1991 | 9.376 | 91 |
| 1990 | 8.411 | 97 |
| 1989 | 8.411 | 97 |
| 1988 | 7.8 | 97 |
| 1987 | 7.5 | 97 |
| 1986 | 8.958 | 85 |