| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 26.68 | 74 |
| 2015 | 28.06 | 73 |
| 2014 | 28.93 | 66 |
| 2013 | 28.59 | 73 |
| 2012 | 29.13 | 68 |
| 2011 | 30.01 | 65 |
| 2010 | 30.11 | 61 |
| 2009 | 30.15 | 59 |
| 2008 | 31.33 | 62 |
| 2007 | 32.49 | 57 |
| 2006 | 34.4 | 51 |
| 2005 | 33.66 | 46 |
| 2004 | 33.9 | 47 |
| 2003 | 34.9 | 39 |
| 2002 | 32.4 | 49 |
| 2001 | 27.04 | 87 |
| 2000 | 28.06 | 80 |
| 1999 | 28.29 | 79 |
| 1998 | 29 | 70 |
| 1997 | 29.53 | 73 |
| 1996 | 28.82 | 80 |
| 1995 | 28.44 | 88 |
| 1994 | 29.02 | 69 |
| 1993 | 29.23 | 71 |
| 1992 | 30.68 | 60 |
| 1991 | 32.72 | 53 |
| 1990 | 36.02 | 35 |
| 1989 | 42.35 | 20 |
| 1988 | 38.49 | 22 |
| 1987 | 37.83 | 26 |
| 1986 | 37.38 | 22 |