| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 9.11 | 10 |
| 2015 | 7.14 | 34 |
| 2014 | 5.27 | 55 |
| 2013 | 4.02 | 72 |
| 2012 | 3.61 | 69 |
| 2011 | 6.31 | 61 |
| 2010 | 3.85 | 103 |
| 2009 | 3.53 | 44 |
| 2008 | -1.06 | 139 |
| 2007 | 6.58 | 74 |
| 2006 | 0.52 | 142 |
| 2005 | 2.46 | 117 |
| 2004 | 6.01 | 69 |
| 2003 | 4.2 | 83 |
| 2002 | 5.74 | 56 |
| 2001 | 5 | 53 |
| 2000 | 4.29 | 85 |
| 1999 | 1.7 | 104 |
| 1998 | 7.34 | 37 |
| 1997 | 3.86 | 83 |
| 1996 | 4.68 | 69 |
| 1995 | 5.37 | 50 |
| 1994 | 1.38 | 97 |
| 1993 | -.5 | 80 |
| 1992 | 6.86 | 39 |
| 1991 | 3.27 | 52 |
| 1990 | 2.69 | 56 |
| 1989 | -.77 | 94 |
| 1988 | 2.34 | 72 |
| 1987 | 9.8 | 20 |
| 1986 | 3.92 | 57 |