| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.8 | 30 |
| 2015 | 3.17 | 77 |
| 2014 | 3.42 | 82 |
| 2013 | 1.13 | 121 |
| 2012 | 2.65 | 82 |
| 2011 | 1.23 | 135 |
| 2010 | 2.67 | 121 |
| 2009 | 0.17 | 70 |
| 2008 | 1.95 | 99 |
| 2007 | 2.48 | 115 |
| 2006 | 2.11 | 129 |
| 2005 | 6.29 | 58 |
| 2004 | 4.45 | 92 |
| 2003 | 6.68 | 61 |
| 2002 | 5.48 | 59 |
| 2001 | 0.88 | 109 |
| 2000 | 4.12 | 88 |
| 1999 | 4.55 | 66 |
| 1998 | 4.44 | 68 |
| 1997 | 3.7 | 86 |
| 1996 | 3.05 | 91 |
| 1995 | 2.89 | 80 |
| 1994 | -2.31 | 109 |
| 1993 | -1.46 | 89 |
| 1992 | -.48 | 85 |
| 1991 | -1.09 | 87 |
| 1990 | 2.55 | 58 |
| 1989 | 1.02 | 82 |
| 1988 | -.85 | 93 |
| 1987 | -.1 | 87 |
| 1986 | 2.89 | 63 |