| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.53 | 104 |
| 2015 | 7.63 | 105 |
| 2014 | 7.73 | 104 |
| 2013 | 7.76 | 103 |
| 2012 | 7.85 | 103 |
| 2011 | 13.63 | 146 |
| 2010 | 10.83 | 133 |
| 2009 | 8.65 | 110 |
| 2008 | 7.9 | 119 |
| 2007 | 12.12 | 153 |
| 2006 | 14.27 | 158 |
| 2005 | 15.9 | 158 |
| 2004 | 15.51 | 158 |
| 2003 | 15.47 | 156 |
| 2002 | 12.72 | 139 |
| 2001 | 13.72 | 147 |
| 2000 | 12.93 | 138 |
| 1999 | 12.48 | 134 |
| 1998 | 12 | 131 |
| 1997 | 13.52 | 145 |
| 1996 | 15 | 154 |
| 1995 | 17.43 | 163 |
| 1994 | 18.57 | 165 |
| 1993 | 19.7 | 168 |
| 1992 | 19.33 | 170 |
| 1991 | 18.9 | 169 |