| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 6.44 | 134 |
| 2014 | 6.25 | 148 |
| 2013 | 6.45 | 159 |
| 2012 | 5.52 | 169 |
| 2011 | 4.2 | 176 |
| 2010 | 4.6 | 171 |
| 2009 | 4.98 | 171 |
| 2008 | 4.94 | 169 |
| 2007 | 5.11 | 171 |
| 2006 | 5.6 | 167 |
| 2005 | 6.2 | 162 |
| 2004 | 5.88 | 150 |
| 2003 | 6.22 | 148 |
| 2002 | 7.76 | 143 |
| 2001 | 12.53 | 111 |
| 2000 | 11.55 | 112 |
| 1999 | 13.17 | 95 |
| 1998 | 11.03 | 105 |
| 1997 | 9.69 | 109 |
| 1996 | 9.75 | 109 |
| 1995 | 12.56 | 85 |
| 1994 | 14.71 | 77 |
| 1993 | 14.01 | 79 |
| 1992 | 20.41 | 42 |
| 1991 | 17.93 | 44 |
| 1990 | 16.22 | 56 |
| 1989 | 16.46 | 53 |
| 1988 | 17.13 | 50 |
| 1987 | 14.54 | 56 |
| 1986 | 12.72 | 60 |