| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.25 | 107 |
| 2015 | 5.09 | 108 |
| 2014 | 4.96 | 111 |
| 2013 | 4.88 | 112 |
| 2012 | 4.83 | 112 |
| 2011 | 4.79 | 113 |
| 2010 | 4.73 | 112 |
| 2009 | 4.66 | 113 |
| 2008 | 4.58 | 113 |
| 2007 | 4.48 | 115 |
| 2006 | 4.37 | 116 |
| 2005 | 4.28 | 118 |
| 2004 | 4.18 | 119 |
| 2003 | 4.1 | 120 |
| 2002 | 4.01 | 120 |
| 2001 | 3.92 | 120 |
| 2000 | 3.84 | 122 |
| 1999 | 3.77 | 123 |
| 1998 | 3.71 | 127 |
| 1997 | 3.64 | 128 |
| 1996 | 3.57 | 129 |
| 1995 | 3.5 | 133 |
| 1994 | 3.45 | 137 |
| 1993 | 3.39 | 137 |
| 1992 | 3.33 | 138 |
| 1991 | 3.27 | 138 |
| 1990 | 3.2 | 140 |
| 1989 | 3.15 | 143 |
| 1988 | 3.1 | 146 |
| 1987 | 3.04 | 150 |
| 1986 | 2.99 | 152 |