| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.33 | 55 |
| 2015 | 2.38 | 86 |
| 2014 | 3.15 | 90 |
| 2013 | 3.31 | 85 |
| 2012 | 1.95 | 98 |
| 2011 | 4.53 | 81 |
| 2010 | 10.39 | 33 |
| 2009 | 0.23 | 69 |
| 2008 | 2.68 | 92 |
| 2007 | 7.12 | 65 |
| 2006 | 6.27 | 73 |
| 2005 | 4.68 | 79 |
| 2004 | 7.83 | 52 |
| 2003 | 5.52 | 70 |
| 2002 | 7.85 | 37 |
| 2001 | 3.72 | 65 |
| 2000 | 11.03 | 25 |
| 1999 | 12.44 | 16 |
| 1998 | -8.29 | 153 |
| 1997 | 4.33 | 81 |
| 1996 | 7.84 | 29 |
| 1995 | 9.92 | 25 |
| 1994 | 9.33 | 25 |
| 1993 | 7.67 | 24 |
| 1992 | 3.4 | 54 |
| 1991 | 11.74 | 17 |
| 1990 | 15.07 | 11 |
| 1989 | 6.76 | 36 |
| 1988 | 10.96 | 19 |
| 1987 | 15.59 | 9 |
| 1986 | 11.49 | 14 |