| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 23.64 | 31 |
| 2015 | 22.45 | 60 |
| 2014 | 22.4 | 59 |
| 2013 | 20.52 | 78 |
| 2012 | 23.9 | 66 |
| 2011 | 24.14 | 64 |
| 2010 | 23.72 | 63 |
| 2009 | 23.39 | 61 |
| 2008 | 23.76 | 64 |
| 2007 | 24.65 | 64 |
| 2006 | 23.09 | 65 |
| 2005 | 21.03 | 70 |
| 2004 | 19.23 | 76 |
| 2003 | 18.56 | 73 |
| 2002 | 18.56 | 74 |
| 2001 | 17.64 | 73 |
| 2000 | 15.14 | 80 |
| 1999 | 14.3 | 86 |
| 1998 | 13.34 | 95 |
| 1997 | 12.54 | 93 |
| 1996 | 12.08 | 91 |
| 1995 | 12.15 | 88 |
| 1994 | 11.84 | 87 |
| 1993 | 12.53 | 86 |
| 1992 | 11.78 | 82 |
| 1991 | 10.1 | 86 |
| 1990 | 11.45 | 77 |
| 1989 | 10.85 | 75 |
| 1988 | 11.16 | 70 |
| 1987 | 11.58 | 67 |
| 1986 | 11.76 | 65 |