| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 11.73 | 147 |
| 2015 | 14.91 | 157 |
| 2014 | 16.09 | 159 |
| 2013 | 15.87 | 158 |
| 2012 | 11.8 | 136 |
| 2011 | 7.86 | 105 |
| 2010 | 6.26 | 66 |
| 2009 | 5.36 | 52 |
| 2008 | 3.65 | 38 |
| 2007 | 3.92 | 43 |
| 2006 | 4.54 | 50 |
| 2005 | 5.3 | 56 |
| 2004 | 4.33 | 42 |
| 2003 | 4.14 | 37 |
| 2002 | 3.3 | 26 |
| 2001 | 3.98 | 37 |
| 2000 | 4.97 | 53 |
| 1999 | 5.7 | 54 |
| 1998 | 3.66 | 35 |
| 1997 | 6.51 | 67 |
| 1996 | 14.71 | 152 |
| 1995 | 8.77 | 105 |
| 1994 | 4.99 | 53 |
| 1993 | 7.95 | 93 |
| 1992 | 15.1 | 151 |
| 1991 | 7.95 | 101 |