| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 9.25 | 65 |
| 2015 | 9.13 | 77 |
| 2014 | 9.28 | 81 |
| 2013 | 9.41 | 80 |
| 2012 | 8.59 | 88 |
| 2011 | 8.84 | 89 |
| 2010 | 8.38 | 90 |
| 2009 | 9.37 | 84 |
| 2008 | 9.39 | 83 |
| 2007 | 10.7 | 74 |
| 2006 | 12.82 | 67 |
| 2005 | 16.69 | 58 |
| 2004 | 17.92 | 56 |
| 2003 | 20.55 | 50 |
| 2002 | 20.61 | 51 |
| 2001 | 22.43 | 47 |
| 2000 | 21.93 | 50 |
| 1999 | 26.24 | 39 |
| 1998 | 27.56 | 38 |
| 1997 | 29.24 | 37 |
| 1996 | 34.14 | 29 |
| 1995 | 52.15 | 7 |
| 1994 | 65.86 | 1 |
| 1993 | 58.58 | 2 |
| 1992 | 52.91 | 4 |
| 1991 | 28.65 | 37 |
| 1990 | 31.69 | 28 |
| 1989 | 23.31 | 46 |
| 1988 | 24.26 | 42 |
| 1987 | 24.24 | 43 |
| 1986 | 26.56 | 37 |