| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 73.4 | 99 |
| 2015 | 73.57 | 96 |
| 2014 | 73.68 | 94 |
| 2013 | 73.93 | 94 |
| 2012 | 74.47 | 93 |
| 2011 | 74.95 | 90 |
| 2010 | 75.38 | 85 |
| 2009 | 75.71 | 79 |
| 2008 | 75.85 | 79 |
| 2007 | 76.69 | 71 |
| 2006 | 75.94 | 81 |
| 2005 | 76.18 | 78 |
| 2004 | 75.93 | 80 |
| 2003 | 75.64 | 83 |
| 2002 | 75.33 | 86 |
| 2001 | 75.75 | 89 |
| 2000 | 76.27 | 84 |
| 1999 | 76.08 | 88 |
| 1998 | 76.23 | 86 |
| 1997 | 75.89 | 94 |
| 1996 | 75.5 | 99 |
| 1995 | 75.89 | 97 |
| 1994 | 75.08 | 102 |
| 1993 | 73.73 | 115 |
| 1992 | 70.85 | 144 |
| 1991 | 66.61 | 172 |
| 1990 | 76.27 | 106 |