| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 63.52 | 100 |
| 2015 | 61.91 | 127 |
| 2014 | 67.01 | 125 |
| 2013 | 65.62 | 131 |
| 2012 | 68.14 | 131 |
| 2011 | 69.45 | 132 |
| 2010 | 68.22 | 126 |
| 2009 | 70.18 | 115 |
| 2008 | 86.93 | 98 |
| 2007 | 86.91 | 93 |
| 2006 | 90.26 | 84 |
| 2005 | 89.64 | 82 |
| 2004 | 85.63 | 90 |
| 2003 | 83.69 | 81 |
| 2002 | 80.77 | 86 |
| 2001 | 81.17 | 81 |
| 2000 | 86.9 | 70 |
| 1999 | 87.9 | 63 |
| 1998 | 92.49 | 60 |
| 1997 | 88.05 | 67 |
| 1996 | 84.49 | 69 |
| 1995 | 80.23 | 70 |
| 1994 | 78.4 | 67 |
| 1993 | 79.73 | 58 |
| 1992 | 76.41 | 65 |
| 1991 | 71.71 | 67 |
| 1990 | 66.5 | 75 |
| 1989 | 64.36 | 69 |
| 1988 | 60.92 | 68 |
| 1987 | 57.41 | 69 |
| 1986 | 53.98 | 74 |