| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.21 | 35 |
| 2015 | 2.44 | 34 |
| 2014 | 2.72 | 31 |
| 2013 | 2.88 | 28 |
| 2012 | 2.95 | 27 |
| 2011 | 3.1 | 25 |
| 2010 | 3.01 | 26 |
| 2009 | 3.12 | 34 |
| 2008 | 2.67 | 36 |
| 2007 | 2.57 | 36 |
| 2006 | 2.03 | 50 |
| 2005 | 2.3 | 46 |
| 2004 | 1.94 | 63 |
| 2003 | 2.28 | 54 |
| 2002 | 1.77 | 74 |
| 2001 | 1.57 | 80 |
| 2000 | 1.45 | 87 |
| 1999 | 1.51 | 84 |
| 1998 | 1.96 | 61 |
| 1997 | 1.77 | 72 |
| 1996 | 1.66 | 77 |
| 1995 | 1.95 | 68 |
| 1994 | 1.28 | 110 |
| 1993 | 1.46 | 104 |
| 1992 | 1.17 | 108 |
| 1991 | 1.23 | 102 |
| 1990 | 1.33 | 96 |
| 1989 | 1.36 | 93 |
| 1988 | 1.52 | 91 |
| 1987 | 1.49 | 91 |
| 1986 | 1.35 | 88 |