| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 9.35 | 125 |
| 2014 | 11.1 | 124 |
| 2013 | 13.45 | 125 |
| 2012 | 12.29 | 135 |
| 2011 | 13.78 | 125 |
| 2010 | 12.23 | 131 |
| 2009 | 13.02 | 123 |
| 2008 | 21.23 | 73 |
| 2007 | 15.7 | 106 |
| 2006 | 18.59 | 90 |
| 2005 | 15.11 | 103 |
| 2004 | 11.19 | 123 |
| 2003 | 6.7 | 146 |
| 2002 | 6.08 | 147 |
| 2001 | 4.96 | 142 |
| 2000 | 5.35 | 137 |
| 1999 | 3.63 | 142 |
| 1998 | 5.12 | 136 |
| 1997 | 4.11 | 140 |
| 1996 | 5.63 | 134 |
| 1995 | 9.97 | 105 |
| 1994 | 11.77 | 88 |
| 1993 | 13.79 | 81 |
| 1992 | 14.29 | 69 |
| 1991 | 14.3 | 65 |
| 1990 | 12.89 | 69 |
| 1989 | 9.69 | 81 |
| 1988 | 11.71 | 68 |
| 1987 | 12.73 | 59 |
| 1986 | 9.54 | 82 |