| 时间 | 值 | 世界排名 |
|---|---|---|
| 2016 | 3.2 | 42 |
| 2015 | 2.5 | 106 |
| 2014 | 2.2 | 115 |
| 2013 | 2.1 | 129 |
| 2012 | 2.7 | 120 |
| 2011 | 2.1 | 127 |
| 2010 | 2.2 | 132 |
| 2009 | 1.8 | 141 |
| 2008 | 1.1 | 140 |
| 2007 | 1.2 | 139 |
| 2006 | 1.2 | 138 |
| 2005 | 1.5 | 130 |
| 2004 | 1.8 | 118 |
| 2003 | 2.4 | 100 |
| 2002 | 3.8 | 67 |
| 2001 | 3.3 | 66 |
| 2000 | 3.2 | 65 |
| 1999 | 3.2 | 69 |
| 1998 | 5.1 | 31 |
| 1997 | 5.3 | 22 |
| 1996 | 5.6 | 17 |
| 1995 | 6.1 | 15 |
| 1994 | 7.4 | 11 |
| 1993 | 8.4 | 4 |
| 1992 | 8.7 | 4 |
| 1991 | 10.5 | 3 |
| 1990 | 8.6 | 4 |
| 1989 | 9 | 5 |
| 1988 | 6.9 | 9 |
| 1987 | 9.6 | 7 |
| 1986 | 9.5 | 6 |