| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.76 | 104 |
| 2015 | 1.84 | 128 |
| 2014 | 3.69 | 132 |
| 2013 | 9.76 | 81 |
| 2012 | 6.47 | 109 |
| 2011 | 8.24 | 100 |
| 2010 | 2.97 | 141 |
| 2009 | 13.42 | 68 |
| 2008 | 15.77 | 75 |
| 2007 | 19.09 | 74 |
| 2006 | 21.66 | 66 |
| 2005 | 11.99 | 96 |
| 2004 | 12.34 | 91 |
| 2003 | 7.83 | 115 |
| 2002 | 4.75 | 126 |
| 2001 | 12.81 | 88 |
| 2000 | 6.32 | 120 |
| 1999 | 1.61 | 147 |
| 1998 | -.78 | 139 |
| 1997 | 3.89 | 139 |
| 1996 | -.6 | 147 |
| 1995 | 9.37 | 103 |
| 1994 | 5.42 | 126 |
| 1993 | 5.58 | 110 |
| 1992 | 0.69 | 120 |
| 1989 | 4.78 | 111 |
| 1988 | 6.86 | 96 |
| 1987 | 2.54 | 108 |
| 1986 | 0.41 | 112 |