| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.19 | 51 |
| 2015 | 2.36 | 78 |
| 2014 | 1.99 | 84 |
| 2013 | 3.6 | 62 |
| 2012 | 3.49 | 69 |
| 2011 | 0.82 | 105 |
| 2010 | 1.37 | 97 |
| 2009 | 3.65 | 89 |
| 2008 | 1.42 | 116 |
| 2007 | 3.77 | 82 |
| 2006 | 1.87 | 106 |
| 2005 | 2.73 | 85 |
| 2004 | 3.47 | 73 |
| 2003 | 4.09 | 53 |
| 2002 | 4.82 | 54 |
| 2001 | 7.58 | 30 |
| 2000 | 3.89 | 51 |
| 1999 | 7.24 | 28 |
| 1998 | 2.71 | 70 |
| 1997 | 2.6 | 70 |
| 1996 | 6.11 | 32 |
| 1995 | 3.16 | 50 |
| 1994 | 0.98 | 70 |
| 1993 | 5.23 | 35 |
| 1992 | 3.21 | 44 |
| 1991 | 4.03 | 45 |
| 1990 | 6.68 | 16 |
| 1989 | 8.16 | 20 |
| 1988 | 4.33 | 28 |
| 1987 | 9.65 | 13 |
| 1986 | 6.41 | 27 |