| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 75.05 | 55 |
| 2014 | 81.86 | 50 |
| 2013 | 82.91 | 54 |
| 2012 | 83.97 | 57 |
| 2011 | 82.58 | 60 |
| 2010 | 80.28 | 57 |
| 2009 | 69.78 | 65 |
| 2008 | 76.19 | 74 |
| 2007 | 73.32 | 74 |
| 2006 | 72.14 | 75 |
| 2005 | 75.09 | 69 |
| 2004 | 69.36 | 73 |
| 2003 | 66.14 | 69 |
| 2002 | 63.9 | 75 |
| 2001 | 68.99 | 63 |
| 2000 | 70.52 | 64 |
| 1999 | 65.67 | 66 |
| 1998 | 70.05 | 56 |
| 1997 | 74.03 | 52 |
| 1996 | 73.86 | 48 |
| 1995 | 75.67 | 43 |
| 1994 | 72.27 | 42 |
| 1993 | 72.19 | 35 |
| 1992 | 69.65 | 44 |
| 1991 | 53.13 | 61 |
| 1990 | 59.77 | 56 |
| 1989 | 73.1 | 34 |
| 1988 | 66.71 | 37 |
| 1987 | 61.51 | 42 |
| 1986 | 73.17 | 31 |