| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 11.2 | 193 |
| 2015 | 11.2 | 193 |
| 2014 | 11.1 | 193 |
| 2013 | 11.1 | 193 |
| 2012 | 11.4 | 193 |
| 2011 | 11.7 | 194 |
| 2010 | 11.9 | 194 |
| 2009 | 12.3 | 194 |
| 2008 | 12.7 | 194 |
| 2007 | 13.2 | 194 |
| 2006 | 13.7 | 192 |
| 2005 | 14.4 | 189 |
| 2004 | 14.8 | 188 |
| 2003 | 15.3 | 186 |
| 2002 | 15.8 | 185 |
| 2001 | 16.3 | 185 |
| 2000 | 16.9 | 183 |
| 1999 | 17.2 | 183 |
| 1998 | 17.6 | 182 |
| 1997 | 18 | 178 |
| 1996 | 18.4 | 178 |
| 1995 | 18.6 | 177 |
| 1994 | 19.1 | 176 |
| 1993 | 19.5 | 173 |
| 1992 | 19.9 | 172 |
| 1991 | 20.3 | 173 |
| 1990 | 20.8 | 171 |
| 1989 | 21.2 | 169 |
| 1988 | 21.8 | 167 |
| 1987 | 22.3 | 166 |
| 1986 | 22.9 | 164 |