| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 79.8 | 52 |
| 2015 | 79.58 | 51 |
| 2014 | 79.36 | 49 |
| 2013 | 79.13 | 49 |
| 2012 | 78.9 | 49 |
| 2011 | 78.67 | 49 |
| 2010 | 78.44 | 49 |
| 2009 | 78.21 | 49 |
| 2008 | 77.98 | 49 |
| 2007 | 77.74 | 49 |
| 2006 | 77.5 | 49 |
| 2005 | 77.26 | 49 |
| 2004 | 77.02 | 48 |
| 2003 | 76.78 | 48 |
| 2002 | 76.53 | 50 |
| 2001 | 76.34 | 50 |
| 2000 | 76.26 | 49 |
| 1999 | 76.18 | 48 |
| 1998 | 76.1 | 48 |
| 1997 | 76.02 | 48 |
| 1996 | 75.94 | 48 |
| 1995 | 75.86 | 47 |
| 1994 | 75.77 | 47 |
| 1993 | 75.69 | 47 |
| 1992 | 75.61 | 45 |
| 1991 | 75.53 | 44 |
| 1990 | 75.35 | 42 |
| 1989 | 75.13 | 43 |
| 1988 | 74.9 | 44 |
| 1987 | 74.67 | 43 |
| 1986 | 74.44 | 43 |