| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 27.18 | 51 |
| 2015 | 27.33 | 50 |
| 2014 | 27.44 | 49 |
| 2013 | 27.65 | 49 |
| 2012 | 27.94 | 50 |
| 2011 | 28.2 | 51 |
| 2010 | 28.37 | 51 |
| 2009 | 28.68 | 52 |
| 2008 | 28.97 | 51 |
| 2007 | 29.25 | 50 |
| 2006 | 29.56 | 51 |
| 2005 | 29.91 | 50 |
| 2004 | 30.15 | 48 |
| 2003 | 30.39 | 46 |
| 2002 | 30.61 | 44 |
| 2001 | 30.77 | 40 |
| 2000 | 30.86 | 38 |
| 1999 | 30.83 | 37 |
| 1998 | 30.74 | 33 |
| 1997 | 30.58 | 30 |
| 1996 | 30.38 | 28 |
| 1995 | 30.15 | 26 |
| 1994 | 29.9 | 23 |
| 1993 | 29.65 | 22 |
| 1992 | 29.43 | 19 |
| 1991 | 29.29 | 18 |
| 1990 | 29.24 | 15 |
| 1989 | 29.4 | 15 |
| 1988 | 29.7 | 15 |
| 1987 | 30.13 | 15 |
| 1986 | 30.63 | 14 |