| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 4.13 | 67 |
| 2014 | 3.92 | 69 |
| 2013 | 4.62 | 55 |
| 2012 | 6.19 | 51 |
| 2011 | 4.46 | 73 |
| 2010 | 5.73 | 53 |
| 2009 | 5.32 | 57 |
| 2008 | 5.74 | 78 |
| 2007 | 5.37 | 94 |
| 2006 | 3.91 | 103 |
| 2005 | 3.39 | 91 |
| 2004 | 2.39 | 104 |
| 2003 | 2.27 | 101 |
| 2002 | 3.94 | 59 |
| 2001 | 2.2 | 94 |
| 2000 | 1.56 | 117 |
| 1999 | 3.87 | 65 |
| 1998 | 2.96 | 80 |
| 1997 | 3.68 | 53 |
| 1996 | 6.28 | 19 |
| 1995 | 4.8 | 29 |
| 1994 | 7.33 | 11 |
| 1993 | 2.16 | 37 |
| 1992 | -.22 | 144 |
| 1991 | -.02 | 136 |
| 1990 | 0.16 | 113 |
| 1989 | 0.26 | 97 |
| 1988 | 0.17 | 98 |
| 1987 | 0.15 | 95 |
| 1986 | 0.14 | 91 |