| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 0.65 | 160 |
| 2014 | 0.82 | 157 |
| 2013 | 1.08 | 146 |
| 2012 | 1.53 | 142 |
| 2011 | 2.15 | 121 |
| 2010 | 1.63 | 136 |
| 2009 | 5.05 | 64 |
| 2008 | 3.94 | 105 |
| 2007 | 3.63 | 118 |
| 2006 | 3.34 | 116 |
| 2005 | 4.44 | 76 |
| 2004 | 2.13 | 112 |
| 2003 | 2.96 | 76 |
| 2002 | 3.17 | 80 |
| 2001 | 2.7 | 83 |
| 2000 | 2.46 | 102 |
| 1999 | 2.8 | 87 |
| 1998 | 3.28 | 69 |
| 1997 | 4.3 | 45 |
| 1996 | 4.55 | 31 |
| 1995 | 3.78 | 38 |
| 1994 | 10.83 | 8 |
| 1993 | 8.52 | 8 |
| 1992 | 3.06 | 27 |
| 1991 | 2.6 | 34 |
| 1990 | 1.91 | 42 |
| 1989 | 7.78 | 7 |
| 1988 | 1.63 | 36 |
| 1987 | 2.53 | 23 |
| 1986 | 0.93 | 40 |