| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 4.9 | 93 |
| 2015 | 9.15 | 73 |
| 2014 | 8.74 | 81 |
| 2013 | 11.74 | 69 |
| 2012 | 10.3 | 78 |
| 2011 | 22.88 | 22 |
| 2010 | 7.71 | 113 |
| 2009 | -4.7 | 156 |
| 2008 | 0.24 | 156 |
| 2007 | 18.75 | 78 |
| 2006 | 19.19 | 77 |
| 2005 | 11.19 | 104 |
| 2004 | 9.55 | 110 |
| 2003 | -.51 | 149 |
| 2002 | 6.08 | 116 |
| 2001 | 82.59 | 12 |
| 2000 | 9.09 | 110 |
| 1999 | 12.98 | 86 |
| 1998 | 13.29 | 64 |
| 1997 | 24.47 | 45 |
| 1996 | 20.09 | 56 |
| 1995 | 24.35 | 50 |
| 1994 | 11.67 | 99 |
| 1993 | 24.54 | 50 |
| 1992 | 26.08 | 41 |
| 1991 | 26.97 | 37 |
| 1990 | 24.24 | 39 |
| 1989 | 31.37 | 30 |
| 1988 | 29.5 | 30 |
| 1987 | 31.53 | 29 |
| 1986 | 24.91 | 34 |