| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 5.17 | 142 |
| 2014 | 5.85 | 150 |
| 2013 | 5.57 | 168 |
| 2012 | 6.73 | 160 |
| 2011 | 6.21 | 163 |
| 2010 | 7.75 | 156 |
| 2009 | 6.29 | 164 |
| 2008 | 8.26 | 152 |
| 2007 | 8.32 | 150 |
| 2006 | 8.72 | 147 |
| 2005 | 10.28 | 139 |
| 2004 | 8.28 | 141 |
| 2003 | 7.41 | 143 |
| 2002 | 6.26 | 146 |
| 2001 | 5.02 | 141 |
| 2000 | 4.69 | 141 |
| 1999 | 5.36 | 136 |
| 1998 | 5.66 | 134 |
| 1997 | 6.86 | 130 |
| 1996 | 8.65 | 120 |
| 1995 | 7.91 | 123 |
| 1994 | 8.25 | 112 |
| 1993 | 8.18 | 113 |
| 1992 | 8.72 | 100 |
| 1991 | 8.46 | 98 |
| 1990 | 8.75 | 92 |
| 1989 | 7.22 | 103 |
| 1988 | 6.11 | 108 |
| 1987 | 6.77 | 100 |
| 1986 | 6.37 | 102 |