| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 55.07 | 68 |
| 2015 | 52.89 | 81 |
| 2014 | 51.63 | 79 |
| 2013 | 48.99 | 83 |
| 2012 | 46.62 | 80 |
| 2011 | 45.56 | 84 |
| 2010 | 44.88 | 90 |
| 2009 | 44.77 | 88 |
| 2008 | 39.54 | 90 |
| 2007 | 37.85 | 101 |
| 2006 | 37.32 | 99 |
| 2005 | 35.82 | 99 |
| 2004 | 34.99 | 97 |
| 2003 | 37.37 | 89 |
| 2002 | 36.76 | 90 |
| 2001 | 35.97 | 89 |
| 2000 | 23.18 | 111 |
| 1999 | 28.32 | 99 |
| 1998 | 28.81 | 92 |
| 1997 | 29.56 | 92 |
| 1996 | 23.75 | 102 |
| 1995 | 25.59 | 99 |
| 1994 | 24.06 | 106 |
| 1993 | 22.71 | 108 |
| 1992 | 27.1 | 93 |
| 1991 | 26.01 | 91 |
| 1990 | 22.39 | 94 |
| 1989 | 16.4 | 113 |
| 1988 | 11.04 | 118 |
| 1987 | 27.32 | 80 |
| 1986 | 27.62 | 80 |