| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 4.3 | 46 |
| 2015 | 4.37 | 52 |
| 2014 | 2.92 | 105 |
| 2013 | 2.19 | 129 |
| 2012 | 2.22 | 120 |
| 2011 | 1.78 | 146 |
| 2010 | 5.15 | 79 |
| 2009 | 4.67 | 35 |
| 2008 | 7.16 | 39 |
| 2007 | 7.09 | 66 |
| 2006 | 6.85 | 69 |
| 2005 | 4.48 | 105 |
| 2004 | 4.09 | 130 |
| 2003 | 3.19 | 123 |
| 2002 | 2.37 | 122 |
| 2001 | 3.54 | 88 |
| 2000 | 5.37 | 69 |
| 1999 | 6.11 | 40 |
| 1998 | 4.04 | 89 |
| 1997 | 5.49 | 66 |
| 1996 | 4.99 | 77 |
| 1995 | 4.64 | 79 |
| 1994 | 3.97 | 83 |
| 1993 | 2.9 | 85 |
| 1992 | 4.43 | 59 |
| 1991 | 1.08 | 107 |
| 1990 | 5.7 | 42 |
| 1989 | 4.97 | 54 |
| 1988 | 5.3 | 70 |
| 1987 | 2.52 | 99 |
| 1986 | 2.65 | 101 |