| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 74.65 | 89 |
| 2015 | 74.85 | 89 |
| 2014 | 74.93 | 89 |
| 2013 | 74.94 | 88 |
| 2012 | 75.34 | 87 |
| 2011 | 75.53 | 86 |
| 2010 | 75.25 | 86 |
| 2009 | 75.23 | 86 |
| 2008 | 75.39 | 84 |
| 2007 | 75.74 | 81 |
| 2006 | 75.36 | 85 |
| 2005 | 75.04 | 89 |
| 2004 | 75.81 | 81 |
| 2003 | 76.6 | 77 |
| 2002 | 76.63 | 78 |
| 2001 | 77.23 | 74 |
| 2000 | 77.69 | 75 |
| 1999 | 77.96 | 78 |
| 1998 | 78.32 | 78 |
| 1997 | 78.38 | 78 |
| 1996 | 78.86 | 79 |
| 1995 | 79.39 | 76 |
| 1994 | 79.66 | 76 |
| 1993 | 80.39 | 65 |
| 1992 | 80.27 | 69 |
| 1991 | 80.76 | 63 |
| 1990 | 80.52 | 68 |