| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 33.27 | 32 |
| 2014 | 30.77 | 39 |
| 2013 | 29.57 | 49 |
| 2012 | 28.81 | 51 |
| 2011 | 28.28 | 51 |
| 2010 | 26.6 | 52 |
| 2009 | 27.22 | 51 |
| 2008 | 29.91 | 45 |
| 2007 | 28.68 | 52 |
| 2006 | 29.69 | 43 |
| 2005 | 30.48 | 39 |
| 2004 | 32.42 | 35 |
| 2003 | 34.77 | 30 |
| 2002 | 31.07 | 35 |
| 2001 | 31.54 | 32 |
| 2000 | 29.42 | 32 |
| 1999 | 25.04 | 38 |
| 1998 | 23.36 | 45 |
| 1997 | 25.37 | 37 |
| 1996 | 21.4 | 47 |
| 1995 | 17.25 | 66 |