| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.03 | 98 |
| 2015 | 1.96 | 99 |
| 2014 | 1.88 | 97 |
| 2013 | 1.76 | 102 |
| 2012 | 1.68 | 110 |
| 2011 | 1.56 | 113 |
| 2010 | 1.43 | 122 |
| 2009 | 1.3 | 129 |
| 2008 | 1.16 | 136 |
| 2007 | 1.01 | 140 |
| 2006 | 0.87 | 151 |
| 2005 | 0.73 | 157 |
| 2004 | 0.59 | 165 |
| 2003 | 0.75 | 158 |
| 2002 | 2.29 | 91 |
| 2001 | 2.38 | 94 |
| 2000 | 2.52 | 85 |
| 1999 | 2.66 | 78 |
| 1998 | 2.79 | 78 |
| 1997 | 2.89 | 73 |
| 1996 | 2.99 | 73 |
| 1995 | 3.07 | 70 |
| 1994 | 3.19 | 69 |
| 1993 | 3.5 | 62 |
| 1992 | 4.8 | 33 |
| 1991 | 5.07 | 26 |
| 1990 | 5.37 | 26 |
| 1989 | 5.66 | 21 |
| 1988 | 5.92 | 19 |
| 1987 | 6.13 | 21 |
| 1986 | 6.28 | 23 |