| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.46 | 102 |
| 2015 | 0.53 | 99 |
| 2014 | 0.59 | 97 |
| 2013 | 0.64 | 94 |
| 2012 | 0.66 | 92 |
| 2011 | 0.67 | 95 |
| 2010 | 0.66 | 97 |
| 2009 | 0.65 | 100 |
| 2008 | 0.65 | 103 |
| 2007 | 0.65 | 105 |
| 2006 | 0.66 | 103 |
| 2005 | 0.68 | 99 |
| 2004 | 0.7 | 102 |
| 2003 | 0.68 | 101 |
| 2002 | 0.63 | 102 |
| 2001 | 0.55 | 101 |
| 2000 | 0.03 | 136 |
| 1999 | -.1 | 145 |
| 1998 | -.12 | 145 |
| 1997 | -.08 | 140 |
| 1996 | 0.01 | 136 |
| 1995 | 0.12 | 131 |
| 1994 | 0.23 | 120 |
| 1993 | 0.32 | 122 |
| 1992 | 0.38 | 116 |
| 1991 | 0.43 | 120 |
| 1990 | 0.84 | 101 |
| 1989 | 0.96 | 101 |
| 1988 | 1.05 | 96 |
| 1987 | 1.2 | 93 |
| 1986 | 1.38 | 83 |