| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 8 | 108 |
| 2015 | 9.14 | 121 |
| 2014 | 11.42 | 137 |
| 2013 | 12.94 | 143 |
| 2012 | 12.27 | 141 |
| 2011 | 11.26 | 134 |
| 2010 | 10.28 | 128 |
| 2009 | 6.82 | 81 |
| 2008 | 5.61 | 71 |
| 2007 | 6.88 | 94 |
| 2006 | 8.95 | 120 |
| 2005 | 10.08 | 127 |
| 2004 | 12.04 | 142 |
| 2003 | 13.73 | 148 |
| 2002 | 18.11 | 166 |
| 2001 | 19.92 | 172 |
| 2000 | 16.22 | 162 |
| 1999 | 14.1 | 151 |
| 1998 | 12.2 | 134 |
| 1997 | 13.7 | 146 |
| 1996 | 13.5 | 142 |
| 1995 | 15.7 | 153 |
| 1994 | 20 | 172 |
| 1993 | 21.4 | 175 |
| 1992 | 13.78 | 140 |
| 1991 | 18.37 | 165 |