| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 6.81 | 36 |
| 2014 | 3.89 | 76 |
| 2013 | 2.61 | 91 |
| 2012 | 2.01 | 97 |
| 2011 | 4.22 | 88 |
| 2010 | 7.38 | 62 |
| 2009 | 12.25 | 15 |
| 2008 | 5.71 | 59 |
| 2007 | 10.61 | 27 |
| 2006 | 11.12 | 38 |
| 2005 | 12.06 | 20 |
| 2004 | 12.66 | 24 |
| 2003 | 11.52 | 27 |
| 2002 | 11 | 19 |
| 2001 | 10.14 | 21 |
| 2000 | 4.36 | 81 |
| 1999 | -2.06 | 136 |
| 1998 | -7.23 | 151 |
| 1997 | 11.44 | 22 |
| 1996 | -.44 | 123 |
| 1995 | -8.32 | 127 |
| 1994 | -9.85 | 123 |
| 1993 | -7.99 | 112 |
| 1992 | 9.63 | 25 |
| 1991 | -1.22 | 90 |
| 1990 | 4.55 | 43 |
| 1989 | -.73 | 93 |
| 1988 | 6.66 | 40 |
| 1987 | 4.32 | 52 |
| 1986 | 0.17 | 84 |