| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 20.03 | 39 |
| 2015 | 19.64 | 68 |
| 2014 | 19.09 | 77 |
| 2013 | 19.1 | 88 |
| 2012 | 20.93 | 77 |
| 2011 | 19.03 | 87 |
| 2010 | 18.84 | 86 |
| 2009 | 19.21 | 82 |
| 2008 | 20.71 | 77 |
| 2007 | 21.79 | 72 |
| 2006 | 22.1 | 69 |
| 2005 | 21.49 | 67 |
| 2004 | 25.14 | 54 |
| 2003 | 19.17 | 68 |
| 2002 | 18.58 | 73 |
| 2001 | 18.68 | 68 |
| 2000 | 20.96 | 55 |
| 1999 | 19.26 | 60 |
| 1998 | 16.7 | 71 |
| 1997 | 15.89 | 71 |
| 1996 | 15.71 | 73 |
| 1995 | 16.28 | 69 |
| 1994 | 18.97 | 59 |
| 1993 | 18.75 | 57 |
| 1992 | 17.27 | 57 |
| 1991 | 16.65 | 55 |
| 1990 | 18.08 | 49 |
| 1989 | 19.34 | 43 |
| 1988 | 18.11 | 46 |
| 1987 | 20.26 | 39 |
| 1986 | 19.74 | 40 |