| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.55 | 85 |
| 2015 | 5.78 | 35 |
| 2014 | 13.02 | 8 |
| 2013 | 8.6 | 17 |
| 2012 | 14.98 | 12 |
| 2011 | 9.48 | 32 |
| 2010 | 10.15 | 17 |
| 2009 | 6.28 | 49 |
| 2008 | 25.06 | 10 |
| 2007 | 9.05 | 34 |
| 2006 | 5.1 | 83 |
| 2005 | 12.72 | 21 |
| 2004 | 8.24 | 38 |
| 2003 | 5.13 | 68 |
| 2002 | 0.92 | 142 |
| 2001 | 6.28 | 53 |
| 2000 | 11.6 | 29 |
| 1999 | 7.56 | 43 |
| 1998 | 9.36 | 48 |
| 1997 | 36.56 | 10 |
| 1996 | 46.89 | 13 |
| 1995 | 0.04 | 157 |
| 1994 | 87.58 | 18 |
| 1993 | 268.15 | 10 |