| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 1.545 | 94 |
| 2015 | 1.828 | 100 |
| 2014 | 2.4 | 101 |
| 2013 | 2.64 | 101 |
| 2012 | 2.858 | 104 |
| 2011 | 3.112 | 98 |
| 2010 | 3.079 | 103 |
| 2009 | 3.273 | 100 |
| 2008 | 3.229 | 127 |
| 2007 | 3.126 | 135 |
| 2006 | 2.952 | 123 |
| 2005 | 2.867 | 114 |
| 2004 | 3.322 | 98 |
| 2003 | 3.387 | 101 |
| 2002 | 3.593 | 106 |
| 2001 | 4.228 | 108 |
| 2000 | 4.235 | 113 |
| 1999 | 4.303 | 121 |
| 1998 | 4.155 | 126 |
| 1997 | 3.928 | 127 |
| 1996 | 3.738 | 126 |
| 1995 | 3.671 | 130 |
| 1994 | 3.612 | 121 |
| 1993 | 3.88 | 114 |
| 1992 | 3.675 | 110 |
| 1991 | 3.745 | 111 |
| 1990 | 7 | 80 |
| 1989 | 5.667 | 89 |
| 1988 | 6.083 | 76 |
| 1987 | 6.292 | 70 |
| 1986 | 5.792 | 84 |