| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 0.425 | 140 |
| 2014 | 0.332 | 151 |
| 2013 | 0.33 | 152 |
| 2012 | 0.486 | 149 |
| 2011 | 0.92 | 147 |
| 2010 | 1.383 | 138 |
| 2009 | 2.323 | 125 |
| 2008 | 1.314 | 155 |
| 2007 | 1.061 | 161 |
| 2006 | 0.979 | 160 |
| 2005 | 0.854 | 158 |
| 2004 | 1.725 | 134 |
| 2003 | 4.375 | 86 |
| 2002 | 3.184 | 111 |
| 2001 | 5.463 | 80 |
| 2000 | 8.458 | 58 |
| 1999 | 8.127 | 68 |
| 1998 | 8.363 | 72 |
| 1997 | 4.129 | 124 |
| 1996 | 7.131 | 84 |
| 1995 | 7.295 | 83 |
| 1994 | 5.087 | 93 |
| 1993 | 5.033 | 95 |
| 1992 | 7.854 | 64 |
| 1991 | 9.063 | 57 |
| 1990 | 8.667 | 59 |
| 1989 | 8.225 | 64 |
| 1988 | 9.275 | 48 |
| 1987 | 9.6 | 39 |
| 1986 | 11.488 | 30 |