| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 0.92 | 110 |
| 2015 | 0.87 | 124 |
| 2014 | 0.86 | 127 |
| 2013 | 0.82 | 127 |
| 2012 | 0.92 | 120 |
| 2011 | 0.84 | 119 |
| 2010 | 0.76 | 125 |
| 2009 | 0.82 | 126 |
| 2008 | 1.19 | 109 |
| 2007 | 1.34 | 95 |
| 2006 | 1.15 | 110 |
| 2005 | 1.18 | 112 |
| 2004 | 1.39 | 97 |
| 2003 | 1.53 | 87 |
| 2002 | 1.81 | 71 |
| 2001 | 1.82 | 68 |
| 2000 | 2.13 | 57 |
| 1999 | 1.7 | 70 |
| 1998 | 1.77 | 68 |
| 1997 | 1.58 | 83 |
| 1996 | 1.61 | 81 |
| 1995 | 1.47 | 96 |
| 1994 | 1.77 | 83 |
| 1993 | 1.82 | 89 |
| 1992 | 2.11 | 70 |
| 1991 | 3.93 | 30 |
| 1990 | 4.62 | 24 |
| 1989 | 7.92 | 9 |
| 1988 | 9.36 | 7 |
| 1987 | 8.75 | 8 |