| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 31.75 | 119 |
| 2015 | 30.45 | 124 |
| 2014 | 29.59 | 125 |
| 2013 | 29.96 | 125 |
| 2012 | 28.89 | 128 |
| 2011 | 30.09 | 128 |
| 2010 | 31.9 | 122 |
| 2009 | 36.71 | 95 |
| 2008 | 45.61 | 58 |
| 2007 | 50.21 | 42 |
| 2006 | 50.26 | 41 |
| 2005 | 48.9 | 49 |
| 2004 | 45.12 | 54 |
| 2003 | 45.65 | 52 |
| 2002 | 45.19 | 55 |
| 2001 | 47.13 | 53 |
| 2000 | 48.47 | 52 |
| 1999 | 47.09 | 53 |
| 1998 | 44.02 | 70 |
| 1997 | 39.34 | 95 |
| 1996 | 36.72 | 115 |
| 1995 | 37.26 | 119 |
| 1994 | 35.54 | 131 |
| 1993 | 34.47 | 138 |
| 1992 | 35.21 | 137 |
| 1991 | 37.79 | 125 |