| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.98 | 72 |
| 2015 | -.05 | 137 |
| 2014 | -.18 | 155 |
| 2013 | -.04 | 169 |
| 2012 | 0.89 | 167 |
| 2011 | 2.96 | 144 |
| 2010 | 1.16 | 155 |
| 2009 | -.49 | 161 |
| 2008 | 3.44 | 160 |
| 2007 | 2.21 | 146 |
| 2006 | 1.36 | 166 |
| 2005 | 0.45 | 170 |
| 2004 | 0.37 | 157 |
| 2003 | 1.93 | 121 |
| 2002 | 2.16 | 113 |
| 2001 | 2.41 | 123 |
| 2000 | 1.04 | 134 |
| 1999 | 0.45 | 138 |
| 1998 | -.14 | 153 |
| 1997 | 0.52 | 158 |
| 1996 | 0.47 | 157 |
| 1995 | 2.53 | 131 |
| 1994 | 2.2 | 132 |
| 1993 | 4.65 | 94 |
| 1992 | 2.28 | 118 |
| 1991 | 9.34 | 69 |
| 1990 | 10.47 | 59 |
| 1989 | 6.44 | 74 |
| 1988 | 5.8 | 77 |
| 1987 | 4.22 | 77 |
| 1986 | 4.23 | 74 |