| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 62.8 | 125 |
| 2015 | 62.4 | 127 |
| 2014 | 62 | 127 |
| 2013 | 61.6 | 129 |
| 2012 | 61.1 | 131 |
| 2011 | 60.6 | 131 |
| 2010 | 60 | 133 |
| 2009 | 59.3 | 133 |
| 2008 | 58.5 | 137 |
| 2007 | 57.7 | 140 |
| 2006 | 56.9 | 142 |
| 2005 | 56.1 | 143 |
| 2004 | 55.3 | 148 |
| 2003 | 54.7 | 150 |
| 2002 | 54.1 | 152 |
| 2001 | 53.6 | 156 |
| 2000 | 53.1 | 160 |
| 1999 | 52.7 | 161 |
| 1998 | 52.3 | 161 |
| 1997 | 52.1 | 161 |
| 1996 | 52 | 162 |
| 1995 | 52 | 161 |
| 1994 | 51.9 | 158 |
| 1993 | 51.9 | 156 |
| 1992 | 51.9 | 155 |
| 1991 | 52 | 154 |
| 1990 | 52.2 | 149 |
| 1989 | 52.1 | 145 |
| 1988 | 52 | 142 |
| 1987 | 52 | 141 |
| 1986 | 52 | 144 |