| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 72.17 | 44 |
| 2015 | 66.87 | 56 |
| 2014 | 62.96 | 58 |
| 2013 | 52.88 | 73 |
| 2012 | 50.1 | 73 |
| 2011 | 39.07 | 98 |
| 2010 | 41.61 | 95 |
| 2009 | 37.48 | 105 |
| 2008 | 28.36 | 125 |
| 2007 | 32.21 | 115 |
| 2006 | 23.37 | 130 |
| 2005 | 19.27 | 141 |
| 2004 | 19.99 | 134 |
| 2003 | 18.01 | 138 |
| 2002 | 17.23 | 139 |
| 2001 | 14.11 | 147 |
| 2000 | 13 | 150 |
| 1999 | 10.78 | 153 |
| 1998 | 10.5 | 149 |
| 1997 | 10.48 | 147 |
| 1996 | 9.91 | 150 |
| 1995 | 7.7 | 154 |
| 1994 | 6.36 | 144 |
| 1993 | 4.89 | 142 |