| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 82.72 | 29 |
| 2015 | 82.61 | 31 |
| 2014 | 82.48 | 32 |
| 2013 | 82.47 | 31 |
| 2012 | 83.84 | 21 |
| 2011 | 83.8 | 23 |
| 2010 | 84.33 | 20 |
| 2009 | 84.35 | 21 |
| 2008 | 84.82 | 19 |
| 2007 | 83.81 | 23 |
| 2006 | 81.31 | 41 |
| 2005 | 78.89 | 58 |
| 2004 | 79.02 | 59 |
| 2003 | 79.07 | 59 |
| 2002 | 81.44 | 46 |
| 2001 | 83.78 | 26 |
| 2000 | 82.68 | 32 |
| 1999 | 83.31 | 31 |
| 1998 | 83.49 | 30 |
| 1997 | 82.26 | 44 |
| 1996 | 81.57 | 52 |
| 1995 | 80.78 | 61 |
| 1994 | 80.28 | 69 |
| 1993 | 79.18 | 77 |
| 1992 | 77.96 | 86 |
| 1991 | 76.57 | 98 |
| 1990 | 77.44 | 90 |