| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.54 | 25 |
| 2015 | 5.55 | 38 |
| 2014 | 4.38 | 60 |
| 2013 | 7.95 | 22 |
| 2012 | 18.01 | 9 |
| 2011 | 9.74 | 31 |
| 2010 | 6.4 | 46 |
| 2009 | 10.98 | 19 |
| 2008 | 24.11 | 13 |
| 2007 | 8.34 | 44 |
| 2006 | 2.81 | 123 |
| 2005 | 13.52 | 18 |
| 2004 | 7.85 | 40 |
| 2003 | 10.76 | 31 |
| 2002 | -1.37 | 166 |
| 2001 | 9.24 | 30 |
| 2000 | 24.32 | 16 |
| 1999 | 3.39 | 79 |
| 1998 | 12.5 | 34 |
| 1997 | 31.11 | 13 |
| 1996 | 26.44 | 26 |
| 1995 | 19.26 | 49 |
| 1994 | 14.85 | 65 |
| 1993 | 9.68 | 72 |
| 1992 | 1.82 | 122 |
| 1991 | 9 | 73 |
| 1990 | 7 | 78 |
| 1989 | 11.66 | 49 |
| 1988 | 4.49 | 86 |
| 1987 | 7.11 | 62 |
| 1986 | 1.68 | 98 |