| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 59.7 | 144 |
| 2015 | 59.7 | 142 |
| 2014 | 59.4 | 143 |
| 2013 | 59.1 | 143 |
| 2012 | 58.7 | 145 |
| 2011 | 58.4 | 145 |
| 2010 | 58 | 145 |
| 2009 | 57.6 | 146 |
| 2008 | 57.1 | 146 |
| 2007 | 56.6 | 146 |
| 2006 | 56.1 | 147 |
| 2005 | 55.5 | 152 |
| 2004 | 55.1 | 151 |
| 2003 | 54.6 | 151 |
| 2002 | 54.2 | 150 |
| 2001 | 53.8 | 153 |
| 2000 | 53.4 | 157 |
| 1999 | 53.1 | 157 |
| 1998 | 52.8 | 158 |
| 1997 | 52.6 | 156 |
| 1996 | 52.5 | 157 |
| 1995 | 52.3 | 155 |
| 1994 | 52.2 | 155 |
| 1993 | 52.2 | 154 |
| 1992 | 52.2 | 150 |
| 1991 | 52.3 | 146 |
| 1990 | 52.4 | 142 |
| 1989 | 52.5 | 137 |
| 1988 | 52.6 | 136 |
| 1987 | 52.8 | 134 |
| 1986 | 53 | 133 |