| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 53.91 | 102 |
| 2015 | 52.72 | 95 |
| 2014 | 51.6 | 84 |
| 2013 | 50.6 | 79 |
| 2012 | 49.78 | 74 |
| 2011 | 49.12 | 70 |
| 2010 | 48.54 | 66 |
| 2009 | 48.49 | 66 |
| 2008 | 48.76 | 63 |
| 2007 | 49.36 | 64 |
| 2006 | 50.29 | 69 |
| 2005 | 51.57 | 75 |
| 2004 | 53.3 | 82 |
| 2003 | 55.32 | 86 |
| 2002 | 57.57 | 92 |
| 2001 | 60.09 | 94 |
| 2000 | 62.89 | 100 |
| 1999 | 65.55 | 103 |
| 1998 | 68.36 | 108 |
| 1997 | 71.21 | 109 |
| 1996 | 73.96 | 111 |
| 1995 | 76.52 | 114 |
| 1994 | 79.14 | 116 |
| 1993 | 81.56 | 119 |
| 1992 | 83.77 | 124 |
| 1991 | 85.81 | 125 |
| 1990 | 87.68 | 127 |
| 1989 | 89.55 | 135 |
| 1988 | 91.25 | 139 |
| 1987 | 92.77 | 147 |
| 1986 | 94.07 | 149 |