| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 8.733 | 74 |
| 2014 | 9.376 | 71 |
| 2013 | 10.13 | 67 |
| 2012 | 10.815 | 67 |
| 2011 | 10.808 | 65 |
| 2010 | 10.446 | 72 |
| 2009 | 10.094 | 86 |
| 2008 | 9.197 | 96 |
| 2007 | 9.778 | 95 |
| 2006 | 10.567 | 84 |
| 2005 | 11.469 | 73 |
| 2004 | 13.251 | 63 |
| 2003 | 13.356 | 73 |
| 2002 | 13.889 | 70 |
| 2001 | 16.208 | 63 |
| 2000 | 17.543 | 57 |
| 1999 | 18.896 | 58 |
| 1998 | 17.704 | 64 |
| 1997 | 10.449 | 109 |
| 1996 | 13.303 | 87 |
| 1995 | 13.141 | 86 |
| 1994 | 9.16 | 101 |
| 1993 | 11.288 | 85 |
| 1992 | 14.534 | 61 |
| 1991 | 14.168 | 60 |
| 1990 | 15.519 | 46 |
| 1989 | 14.623 | 49 |
| 1988 | 12.681 | 51 |
| 1987 | 11.942 | 56 |
| 1986 | 12.333 | 54 |