| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.62 | 68 |
| 2015 | 2.68 | 71 |
| 2014 | 2.7 | 70 |
| 2013 | 2.67 | 70 |
| 2012 | 2.78 | 70 |
| 2011 | 2.63 | 75 |
| 2010 | 2.24 | 86 |
| 2009 | 2.28 | 84 |
| 2008 | 2.23 | 91 |
| 2007 | 2 | 103 |
| 2006 | 2.07 | 100 |
| 2005 | 2.02 | 100 |
| 2004 | 1.93 | 103 |
| 2003 | 1.73 | 116 |
| 2002 | 1.58 | 125 |
| 2001 | 1.93 | 108 |
| 2000 | 2.26 | 95 |
| 1999 | 2.02 | 100 |
| 1998 | 1.38 | 127 |
| 1997 | 1.2 | 138 |
| 1996 | 1.28 | 139 |
| 1995 | 1.9 | 112 |
| 1994 | 2.12 | 107 |
| 1993 | 1.75 | 124 |
| 1992 | 1.82 | 121 |
| 1991 | 1.57 | 132 |
| 1990 | 1.32 | 146 |
| 1989 | 1.04 | 159 |
| 1988 | 0.79 | 175 |
| 1987 | 0.72 | 179 |
| 1986 | 0.52 | 184 |