| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.76 | 62 |
| 2015 | 2.94 | 60 |
| 2014 | 3.1 | 57 |
| 2013 | 3.21 | 56 |
| 2012 | 3.24 | 56 |
| 2011 | 3.21 | 56 |
| 2010 | 3.12 | 62 |
| 2009 | 3.03 | 64 |
| 2008 | 2.96 | 70 |
| 2007 | 2.91 | 72 |
| 2006 | 2.89 | 73 |
| 2005 | 2.88 | 74 |
| 2004 | 2.86 | 72 |
| 2003 | 2.84 | 71 |
| 2002 | 2.82 | 75 |
| 2001 | 2.82 | 77 |
| 2000 | 1.79 | 109 |
| 1999 | 0.79 | 152 |
| 1998 | 0.77 | 151 |
| 1997 | 0.74 | 159 |
| 1996 | 0.72 | 157 |
| 1995 | 0.69 | 162 |
| 1994 | 0.68 | 167 |
| 1993 | 0.79 | 163 |
| 1992 | 1.07 | 148 |
| 1991 | 1.45 | 136 |
| 1990 | 1.92 | 125 |
| 1989 | 2.91 | 98 |
| 1988 | 3.77 | 80 |
| 1987 | 3.89 | 79 |
| 1986 | 3.86 | 79 |