| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 22.2 | 23 |
| 2015 | 21.81 | 20 |
| 2014 | 21.32 | 14 |
| 2013 | 20.97 | 8 |
| 2012 | 20.72 | 8 |
| 2011 | 20.47 | 7 |
| 2010 | 20.13 | 6 |
| 2009 | 20.12 | 8 |
| 2008 | 20.15 | 8 |
| 2007 | 20.28 | 7 |
| 2006 | 20.58 | 7 |
| 2005 | 21.05 | 7 |
| 2004 | 21.62 | 8 |
| 2003 | 22.3 | 9 |
| 2002 | 23.07 | 10 |
| 2001 | 23.9 | 11 |
| 2000 | 24.78 | 12 |
| 1999 | 25.82 | 14 |
| 1998 | 26.9 | 16 |
| 1997 | 27.97 | 20 |
| 1996 | 28.95 | 21 |
| 1995 | 29.82 | 23 |
| 1994 | 30.49 | 26 |
| 1993 | 30.97 | 27 |
| 1992 | 31.31 | 27 |
| 1991 | 31.56 | 26 |
| 1990 | 31.78 | 26 |
| 1989 | 32.07 | 25 |
| 1988 | 32.35 | 25 |
| 1987 | 32.58 | 25 |
| 1986 | 32.68 | 23 |