| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.05 | 19 |
| 2015 | 15.52 | 8 |
| 2014 | 7.83 | 20 |
| 2013 | 6.76 | 34 |
| 2012 | 5.07 | 70 |
| 2011 | 8.44 | 44 |
| 2010 | 6.85 | 41 |
| 2009 | 11.66 | 15 |
| 2008 | 14.11 | 38 |
| 2007 | 8.99 | 35 |
| 2006 | 9.69 | 30 |
| 2005 | 12.68 | 23 |
| 2004 | 10.86 | 29 |
| 2003 | 13.68 | 24 |
| 2002 | 15.79 | 16 |
| 2001 | 21.46 | 13 |
| 2000 | 20.78 | 17 |
| 1999 | 85.74 | 6 |
| 1998 | 27.67 | 16 |
| 1997 | 14.77 | 35 |
| 1996 | 47.74 | 12 |
| 1995 | 197.47 | 8 |
| 1994 | 307.63 | 11 |
| 1993 | 874.62 | 8 |