| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 19.97 | 30 |
| 2015 | 19.24 | 40 |
| 2014 | 20.55 | 35 |
| 2013 | 21.53 | 37 |
| 2012 | 18.11 | 49 |
| 2011 | 22.28 | 37 |
| 2010 | 22.53 | 35 |
| 2009 | 18.92 | 44 |
| 2008 | 23.55 | 36 |
| 2007 | 21.23 | 44 |
| 2006 | 19.09 | 50 |
| 2005 | 19.56 | 50 |
| 2004 | 20.38 | 50 |
| 2003 | 18.28 | 53 |
| 2002 | 14.92 | 63 |
| 2001 | 14.75 | 68 |
| 2000 | 15.82 | 65 |
| 1999 | 16.37 | 64 |
| 1998 | 16.71 | 68 |
| 1997 | 17.82 | 64 |
| 1996 | 19.88 | 59 |
| 1995 | 20.11 | 57 |
| 1994 | 19.64 | 58 |
| 1993 | 17.78 | 64 |
| 1992 | 15.82 | 69 |
| 1991 | 17.01 | 67 |