| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 83 | 8 |
| 2015 | 83.01 | 8 |
| 2014 | 83.03 | 8 |
| 2013 | 83.12 | 8 |
| 2012 | 83.22 | 8 |
| 2011 | 83.32 | 9 |
| 2010 | 83.43 | 9 |
| 2009 | 83.52 | 8 |
| 2008 | 83.61 | 7 |
| 2007 | 83.93 | 7 |
| 2006 | 84.26 | 7 |
| 2005 | 84.57 | 5 |
| 2004 | 84.86 | 5 |
| 2003 | 85.13 | 4 |
| 2002 | 85.36 | 4 |
| 2001 | 85.58 | 3 |
| 2000 | 85.78 | 3 |
| 1999 | 86.03 | 4 |
| 1998 | 86.15 | 4 |
| 1997 | 86.37 | 4 |
| 1996 | 86.66 | 4 |
| 1995 | 87.03 | 4 |
| 1994 | 86.47 | 4 |
| 1993 | 85.93 | 5 |
| 1992 | 85.43 | 5 |
| 1991 | 85.04 | 5 |
| 1990 | 84.78 | 5 |