| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 77.1 | 73 |
| 2015 | 77.14 | 72 |
| 2014 | 77.18 | 72 |
| 2013 | 77.25 | 70 |
| 2012 | 77.3 | 69 |
| 2011 | 77.35 | 67 |
| 2010 | 77.39 | 67 |
| 2009 | 77.44 | 67 |
| 2008 | 77.49 | 65 |
| 2007 | 77.36 | 65 |
| 2006 | 77.11 | 70 |
| 2005 | 76.87 | 72 |
| 2004 | 76.59 | 75 |
| 2003 | 76.44 | 80 |
| 2002 | 76.42 | 81 |
| 2001 | 76.2 | 84 |
| 2000 | 76.18 | 86 |
| 1999 | 76.16 | 85 |
| 1998 | 76.14 | 87 |
| 1997 | 76.06 | 90 |
| 1996 | 75.97 | 94 |
| 1995 | 75.83 | 98 |
| 1994 | 75.69 | 99 |
| 1993 | 75.71 | 98 |
| 1992 | 76.4 | 96 |
| 1991 | 76.63 | 97 |
| 1990 | 76.73 | 98 |