| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 26.12 | 47 |
| 2014 | 24.79 | 55 |
| 2013 | 25.25 | 61 |
| 2012 | 23.99 | 65 |
| 2011 | 23.63 | 65 |
| 2010 | 22.18 | 70 |
| 2009 | 22.94 | 64 |
| 2008 | 27.16 | 53 |
| 2007 | 25.93 | 57 |
| 2006 | 25.81 | 57 |
| 2005 | 24.68 | 56 |
| 2004 | 24.36 | 56 |
| 2003 | 22.31 | 54 |
| 2002 | 23.91 | 51 |
| 2001 | 22.97 | 52 |
| 2000 | 23.2 | 51 |
| 1999 | 22.28 | 50 |
| 1998 | 22.13 | 52 |
| 1997 | 22.05 | 49 |
| 1996 | 19.99 | 57 |
| 1995 | 19.89 | 57 |
| 1994 | 18.43 | 63 |
| 1993 | 18.25 | 59 |
| 1992 | 17.64 | 55 |
| 1991 | 15.59 | 60 |
| 1990 | 14.91 | 64 |
| 1989 | 13.79 | 64 |
| 1988 | 13.32 | 61 |
| 1987 | 10.84 | 73 |
| 1986 | 9.64 | 79 |