| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 77.9 | 10 |
| 2015 | 77.75 | 10 |
| 2014 | 77.61 | 12 |
| 2013 | 77.36 | 12 |
| 2012 | 77.14 | 13 |
| 2011 | 77.06 | 14 |
| 2010 | 77.97 | 11 |
| 2009 | 78.94 | 10 |
| 2008 | 79.87 | 8 |
| 2007 | 80.78 | 7 |
| 2006 | 81.65 | 6 |
| 2005 | 82.48 | 6 |
| 2004 | 83.35 | 6 |
| 2003 | 80.17 | 7 |
| 2002 | 76.58 | 13 |
| 2001 | 72.63 | 19 |
| 2000 | 68.36 | 28 |
| 1999 | 63.9 | 37 |
| 1998 | 65.66 | 31 |
| 1997 | 67.36 | 31 |
| 1996 | 67.42 | 30 |
| 1995 | 67.46 | 31 |
| 1994 | 67.42 | 32 |
| 1993 | 67.37 | 34 |
| 1992 | 67.31 | 32 |
| 1991 | 67.22 | 31 |
| 1990 | 67.1 | 30 |