| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.642 | 90 |
| 2015 | 5.578 | 103 |
| 2014 | 5.526 | 115 |
| 2013 | 5.767 | 116 |
| 2012 | 5.68 | 119 |
| 2011 | 6.663 | 109 |
| 2010 | 7.673 | 104 |
| 2009 | 8.566 | 102 |
| 2008 | 8.751 | 101 |
| 2007 | 8.691 | 105 |
| 2006 | 9.779 | 94 |
| 2005 | 10.185 | 89 |
| 2004 | 10.079 | 92 |
| 2003 | 9.472 | 98 |
| 2002 | 9.139 | 103 |
| 2001 | 12.402 | 83 |
| 2000 | 10.907 | 103 |
| 1999 | 11.776 | 98 |
| 1998 | 16.777 | 68 |
| 1997 | 16.276 | 67 |
| 1996 | 14.84 | 80 |
| 1995 | 14.682 | 80 |
| 1994 | 15.057 | 63 |
| 1993 | 14.683 | 66 |
| 1992 | 19.479 | 38 |
| 1991 | 23.074 | 29 |
| 1990 | 24.118 | 21 |
| 1989 | 19.27 | 27 |
| 1988 | 15.921 | 30 |
| 1987 | 13.338 | 44 |
| 1986 | 17.534 | 20 |