| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 36.4 | 93 |
| 2015 | 36.11 | 98 |
| 2014 | 34.67 | 103 |
| 2013 | 34.13 | 102 |
| 2012 | 35.06 | 101 |
| 2011 | 34.33 | 105 |
| 2010 | 36.82 | 94 |
| 2009 | 33.67 | 112 |
| 2008 | 35.73 | 111 |
| 2007 | 36.37 | 106 |
| 2006 | 37.55 | 100 |
| 2005 | 35.75 | 109 |
| 2004 | 34.93 | 114 |
| 2003 | 35.22 | 112 |
| 2002 | 34.22 | 119 |
| 2001 | 39.14 | 95 |
| 2000 | 45.64 | 61 |
| 1999 | 39.85 | 95 |
| 1998 | 38.79 | 99 |
| 1997 | 43.13 | 78 |
| 1996 | 44.74 | 71 |
| 1995 | 47.46 | 58 |
| 1994 | 48.28 | 58 |
| 1993 | 50.06 | 49 |
| 1992 | 52.09 | 44 |
| 1991 | 55.35 | 34 |