| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 61.4 | 132 |
| 2015 | 61.6 | 133 |
| 2014 | 61.6 | 131 |
| 2013 | 61.5 | 131 |
| 2012 | 61.2 | 130 |
| 2011 | 61 | 130 |
| 2010 | 60.8 | 128 |
| 2009 | 60.4 | 128 |
| 2008 | 59.9 | 129 |
| 2007 | 59.4 | 129 |
| 2006 | 58.8 | 130 |
| 2005 | 58 | 130 |
| 2004 | 57.2 | 133 |
| 2003 | 56.3 | 140 |
| 2002 | 55.4 | 143 |
| 2001 | 54.6 | 146 |
| 2000 | 53.9 | 150 |
| 1999 | 53.2 | 156 |
| 1998 | 52.8 | 159 |
| 1997 | 52.4 | 158 |
| 1996 | 52.1 | 160 |
| 1995 | 51.9 | 163 |
| 1994 | 51.8 | 161 |
| 1993 | 51.7 | 157 |
| 1992 | 51.8 | 157 |
| 1991 | 52 | 155 |
| 1990 | 52.3 | 145 |
| 1989 | 52.5 | 138 |
| 1988 | 52.6 | 137 |
| 1987 | 52.8 | 135 |
| 1986 | 52.9 | 134 |