| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.952 | 74 |
| 2015 | 8.073 | 83 |
| 2014 | 9.694 | 68 |
| 2013 | 11.051 | 56 |
| 2012 | 11.135 | 63 |
| 2011 | 10.915 | 63 |
| 2010 | 9.91 | 77 |
| 2009 | 12.36 | 61 |
| 2008 | 13.873 | 53 |
| 2007 | 12.861 | 66 |
| 2006 | 11.891 | 69 |
| 2005 | 16.615 | 43 |
| 2004 | 14.47 | 54 |
| 2003 | 17.663 | 42 |
| 2002 | 20.632 | 32 |
| 2001 | 20.057 | 45 |
| 2000 | 34.596 | 13 |
| 1999 | 35.369 | 18 |
| 1998 | 39.412 | 18 |
| 1997 | 50.05 | 10 |
| 1996 | 55.967 | 11 |
| 1995 | 51.018 | 12 |
| 1994 | 55.573 | 11 |
| 1993 | 53.877 | 12 |
| 1992 | 45.512 | 10 |
| 1991 | 41.148 | 9 |
| 1990 | 41.813 | 7 |
| 1989 | 37.273 | 8 |
| 1988 | 39.794 | 6 |
| 1987 | 49.414 | 2 |
| 1986 | 65.78 | 2 |