| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 12 | 6 |
| 2015 | 7.01 | 35 |
| 2014 | 7.31 | 33 |
| 2013 | 7.7 | 39 |
| 2012 | 12.95 | 10 |
| 2011 | 16.58 | 10 |
| 2010 | 19.38 | 4 |
| 2009 | 14.65 | 10 |
| 2008 | 12.89 | 18 |
| 2007 | 7.77 | 54 |
| 2006 | 17.58 | 13 |
| 2005 | 12.67 | 15 |
| 2004 | 7.6 | 55 |
| 2003 | 18.33 | 9 |
| 2002 | 10.11 | 21 |
| 2001 | 10.13 | 22 |
| 2000 | 8.5 | 39 |
| 1999 | 8.6 | 28 |
| 1998 | 8.55 | 30 |
| 1997 | 8.22 | 36 |
| 1996 | 17.16 | 8 |
| 1995 | 13.05 | 15 |
| 1994 | 10.69 | 20 |
| 1993 | 10.3 | 13 |
| 1992 | 7.58 | 32 |
| 1991 | 19.86 | 7 |
| 1990 | 16.23 | 9 |
| 1989 | 34.88 | 1 |
| 1988 | -2.26 | 98 |
| 1987 | -16.06 | 107 |
| 1986 | 15.91 | 9 |