| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 55.8 | 161 |
| 2015 | 55.7 | 160 |
| 2014 | 55.6 | 160 |
| 2013 | 55.6 | 159 |
| 2012 | 55.5 | 158 |
| 2011 | 55.5 | 156 |
| 2010 | 55.4 | 156 |
| 2009 | 55.4 | 156 |
| 2008 | 55.4 | 154 |
| 2007 | 55.3 | 154 |
| 2006 | 55.2 | 154 |
| 2005 | 55.1 | 153 |
| 2004 | 54.9 | 154 |
| 2003 | 54.7 | 149 |
| 2002 | 54.6 | 149 |
| 2001 | 54.3 | 148 |
| 2000 | 54.1 | 147 |
| 1999 | 53.7 | 148 |
| 1998 | 53.2 | 149 |
| 1997 | 52.8 | 152 |
| 1996 | 52.5 | 155 |
| 1995 | 52.2 | 157 |
| 1994 | 51.8 | 163 |
| 1993 | 51.4 | 165 |
| 1992 | 51.1 | 164 |
| 1991 | 50.9 | 167 |
| 1990 | 50.7 | 170 |
| 1989 | 50.2 | 172 |
| 1988 | 49.7 | 181 |
| 1987 | 49.4 | 184 |
| 1986 | 49 | 186 |