| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 29.71 | 49 |
| 2015 | 26.62 | 87 |
| 2014 | 26.29 | 90 |
| 2013 | 25.45 | 99 |
| 2012 | 24.37 | 103 |
| 2011 | 25.1 | 101 |
| 2010 | 24.4 | 105 |
| 2009 | 21.95 | 116 |
| 2008 | 22.69 | 115 |
| 2007 | 23.88 | 113 |
| 2006 | 24.92 | 105 |
| 2005 | 23.71 | 114 |
| 2004 | 24.24 | 115 |
| 2003 | 26.03 | 95 |
| 2002 | 23.5 | 117 |
| 2001 | 24.3 | 109 |
| 2000 | 25.39 | 99 |
| 1999 | 32.61 | 45 |
| 1998 | 33.83 | 34 |
| 1997 | 34.54 | 33 |
| 1996 | 29.57 | 76 |
| 1995 | 29.98 | 75 |
| 1994 | 30.44 | 62 |
| 1993 | 35.04 | 38 |
| 1992 | 39.09 | 29 |
| 1991 | 35.59 | 41 |
| 1990 | 44.49 | 19 |