| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.512 | 100 |
| 2015 | 6.052 | 99 |
| 2014 | 6.066 | 106 |
| 2013 | 5.815 | 115 |
| 2012 | 6.251 | 111 |
| 2011 | 6.04 | 115 |
| 2010 | 6.658 | 114 |
| 2009 | 7.459 | 112 |
| 2008 | 8.133 | 111 |
| 2007 | 7.28 | 130 |
| 2006 | 5.968 | 139 |
| 2005 | 4.843 | 148 |
| 2004 | 6.6 | 128 |
| 2003 | 6.6 | 124 |
| 2002 | 6.6 | 131 |
| 2001 | 6.975 | 132 |
| 2000 | 6.7 | 136 |
| 1999 | 6.358 | 137 |
| 1998 | 6.55 | 134 |
| 1997 | 6.342 | 131 |
| 1996 | 6.767 | 127 |
| 1995 | 8.117 | 122 |
| 1994 | 7.892 | 117 |
| 1993 | 8.896 | 106 |
| 1992 | 9.996 | 91 |
| 1991 | 10.217 | 83 |
| 1990 | 10.571 | 78 |
| 1989 | 10 | 83 |
| 1988 | 9.425 | 80 |
| 1987 | 9.6 | 77 |
| 1986 | 9.892 | 76 |