| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 4.83 | 143 |
| 2014 | 4.69 | 155 |
| 2013 | 4.7 | 171 |
| 2012 | 5.71 | 165 |
| 2011 | 6.79 | 161 |
| 2010 | 6.61 | 160 |
| 2009 | 12.34 | 127 |
| 2008 | 12.8 | 129 |
| 2007 | 11.89 | 140 |
| 2006 | 11.15 | 136 |
| 2005 | 7.5 | 154 |
| 2004 | 10.6 | 128 |
| 2003 | 13.58 | 103 |
| 2002 | 12.59 | 107 |
| 2001 | 14.26 | 94 |
| 2000 | 11.07 | 119 |
| 1999 | 12.42 | 103 |
| 1998 | 15.78 | 75 |
| 1997 | 15.35 | 75 |
| 1996 | 15.89 | 71 |
| 1995 | 18.31 | 61 |
| 1994 | 18.67 | 60 |
| 1993 | 24.63 | 35 |
| 1992 | 9.77 | 94 |
| 1991 | 12.17 | 75 |
| 1990 | 9.56 | 87 |
| 1989 | 7.95 | 97 |
| 1988 | 5.02 | 110 |
| 1987 | 4.55 | 110 |
| 1986 | 6.55 | 99 |