| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 21.87 | 5 |
| 2014 | 23.79 | 4 |
| 2013 | 27.28 | 4 |
| 2012 | 21.27 | 7 |
| 2011 | 7.62 | 53 |
| 2010 | 7.41 | 32 |
| 2009 | 8.42 | 29 |
| 2008 | 8.71 | 93 |
| 2007 | 7.95 | 52 |
| 2006 | 13.97 | 7 |
| 2005 | 15.41 | 13 |
| 2004 | 11.43 | 25 |
| 2003 | 9.58 | 37 |
| 2002 | 14.74 | 19 |
| 2001 | 22.7 | 12 |
| 2000 | 29.58 | 11 |
| 1999 | 44.8 | 11 |
| 1998 | 29.75 | 14 |
| 1997 | 9.14 | 47 |
| 1996 | 37.6 | 19 |
| 1995 | 83.33 | 13 |
| 1994 | 34.65 | 38 |
| 1993 | 22.77 | 37 |
| 1992 | 23.75 | 31 |
| 1991 | 12.62 | 57 |
| 1990 | 11.82 | 53 |
| 1989 | 12.45 | 47 |
| 1988 | 33.91 | 20 |
| 1987 | 25.16 | 20 |
| 1986 | 14.05 | 39 |