| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 1.558 | 93 |
| 2015 | 1.809 | 101 |
| 2014 | 2.536 | 96 |
| 2013 | 2.891 | 95 |
| 2012 | 3.701 | 79 |
| 2011 | 4.153 | 72 |
| 2010 | 3.857 | 77 |
| 2009 | 3.483 | 96 |
| 2008 | 5.871 | 73 |
| 2007 | 5.174 | 79 |
| 2006 | 4.503 | 83 |
| 2005 | 3.722 | 90 |
| 2004 | 3.874 | 81 |
| 2003 | 4.251 | 87 |
| 2002 | 4.948 | 82 |
| 2001 | 5.793 | 77 |
| 2000 | 7.938 | 67 |
| 1999 | 7.948 | 74 |
| 1998 | 13.288 | 39 |
| 1997 | 10.805 | 55 |
| 1996 | 7.5 | 79 |
| 1995 | 8.833 | 69 |
| 1994 | 8.5 | 63 |
| 1993 | 8.583 | 60 |
| 1992 | 10 | 55 |
| 1991 | 10 | 54 |
| 1990 | 10 | 48 |
| 1989 | 10 | 48 |
| 1988 | 10 | 43 |
| 1987 | 10 | 37 |
| 1986 | 10 | 40 |