| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 6.31 | 48 |
| 2014 | 4.52 | 57 |
| 2013 | 4.52 | 56 |
| 2012 | 3.13 | 96 |
| 2011 | 10.61 | 28 |
| 2010 | 4.29 | 69 |
| 2009 | 6.87 | 47 |
| 2008 | 8.23 | 51 |
| 2007 | 10.98 | 35 |
| 2006 | 13.9 | 28 |
| 2005 | 6.01 | 52 |
| 2004 | 3.86 | 73 |
| 2003 | 6.92 | 32 |
| 2002 | 3.04 | 84 |
| 2001 | 1.45 | 115 |
| 2000 | 0.79 | 136 |
| 1999 | 0.61 | 136 |
| 1998 | 0.62 | 141 |
| 1997 | 3.06 | 65 |
| 1996 | 0 | 166 |
| 1995 | 0.27 | 141 |