| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2014 | 33.93 | 33 |
| 2013 | 34.02 | 39 |
| 2012 | 33.67 | 41 |
| 2011 | 31.64 | 44 |
| 2010 | 26.76 | 51 |
| 2009 | 25.52 | 55 |
| 2008 | 23.45 | 66 |
| 2007 | 26.04 | 56 |
| 2006 | 29.26 | 45 |
| 2005 | 27.97 | 49 |
| 2004 | 24.72 | 55 |
| 2003 | 21.08 | 61 |
| 2002 | 22.87 | 55 |
| 2001 | 21.88 | 57 |
| 2000 | 20.69 | 56 |
| 1999 | 16.65 | 71 |
| 1998 | 12.75 | 98 |
| 1997 | 10.12 | 107 |
| 1996 | 10.77 | 99 |
| 1995 | 8.77 | 120 |
| 1994 | 6.95 | 119 |
| 1993 | 7.28 | 119 |