| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 73.95 | 47 |
| 2015 | 73.49 | 57 |
| 2014 | 73.96 | 65 |
| 2013 | 72.73 | 75 |
| 2012 | 74.59 | 71 |
| 2011 | 75.27 | 69 |
| 2010 | 66.48 | 78 |
| 2009 | 56.68 | 94 |
| 2008 | 64.17 | 102 |
| 2007 | 64.59 | 92 |
| 2006 | 67.69 | 80 |
| 2005 | 68.41 | 79 |
| 2004 | 73.79 | 66 |
| 2003 | 69.56 | 63 |
| 2002 | 68.72 | 67 |
| 2001 | 66.22 | 69 |
| 2000 | 62.93 | 77 |
| 1999 | 52.33 | 96 |
| 1998 | 47.93 | 106 |
| 1997 | 55 | 88 |
| 1996 | 52.5 | 93 |
| 1995 | 48.29 | 107 |
| 1994 | 44.09 | 104 |
| 1993 | 43.3 | 96 |
| 1992 | 42.83 | 98 |
| 1991 | 35.15 | 105 |
| 1990 | 32.21 | 120 |
| 1989 | 44.95 | 86 |
| 1988 | 46.63 | 81 |
| 1987 | 48.94 | 71 |