| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.66 | 63 |
| 2015 | 1.32 | 139 |
| 2014 | 0.75 | 160 |
| 2013 | 0.76 | 155 |
| 2012 | 0.64 | 167 |
| 2011 | 0.81 | 164 |
| 2010 | 0.24 | 173 |
| 2009 | 0.49 | 163 |
| 2008 | 1.71 | 146 |
| 2007 | 0.38 | 178 |
| 2006 | 0.58 | 171 |
| 2005 | 1.19 | 149 |
| 2004 | 2.29 | 107 |
| 2003 | 2.69 | 87 |
| 2002 | 2.74 | 90 |
| 2001 | 2.2 | 93 |
| 2000 | -.13 | 168 |
| 1999 | 3.3 | 75 |
| 1998 | 3.11 | 76 |
| 1997 | 2.57 | 74 |
| 1996 | 1.98 | 70 |
| 1995 | 1.85 | 69 |
| 1994 | 2.54 | 40 |
| 1993 | 2.5 | 32 |
| 1992 | 0.98 | 66 |
| 1991 | 0.94 | 73 |
| 1990 | 0.83 | 73 |
| 1989 | 1.15 | 53 |
| 1988 | 1.19 | 45 |
| 1987 | 0.88 | 56 |
| 1986 | 0.53 | 62 |