| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | -.36 | 125 |
| 2014 | 11.93 | 10 |
| 2013 | -2.21 | 143 |
| 2012 | 10.13 | 26 |
| 2011 | 1.25 | 94 |
| 2010 | 4.53 | 48 |
| 2009 | 8.02 | 49 |
| 2008 | 9.05 | 31 |
| 2007 | 17.27 | 16 |
| 2006 | 7.27 | 45 |
| 2005 | 12.44 | 14 |
| 2004 | 4.22 | 56 |
| 2003 | 6.95 | 31 |
| 2002 | 22.56 | 8 |
| 2001 | 9.59 | 19 |
| 2000 | 6.81 | 30 |
| 1999 | 2.01 | 83 |
| 1998 | 32.29 | 6 |
| 1997 | 19.72 | 10 |
| 1996 | 7.18 | 26 |
| 1995 | 15.72 | 4 |
| 1994 | 19.4 | 8 |
| 1993 | 16.77 | 9 |
| 1992 | 26.69 | 5 |
| 1991 | 38.95 | 2 |
| 1990 | 6.54 | 18 |
| 1989 | 4.71 | 36 |
| 1988 | 38.94 | 2 |
| 1987 | 109.51 | 1 |
| 1986 | 17.83 | 7 |