| 时间 | 值 （人/平方公里） | 世界排名 |
|---|---|---|
| 2016 | 31.1 | 168 |
| 2015 | 31 | 168 |
| 2014 | 31 | 164 |
| 2013 | 31.1 | 164 |
| 2012 | 31.2 | 163 |
| 2011 | 31.3 | 164 |
| 2010 | 31.4 | 163 |
| 2009 | 31.5 | 163 |
| 2008 | 31.5 | 161 |
| 2007 | 31.6 | 160 |
| 2006 | 31.8 | 160 |
| 2005 | 32 | 159 |
| 2004 | 32.1 | 158 |
| 2003 | 32.3 | 157 |
| 2002 | 32.5 | 154 |
| 2001 | 32.7 | 153 |
| 2000 | 33 | 152 |
| 1999 | 32.8 | 149 |
| 1998 | 32.7 | 148 |
| 1997 | 33 | 146 |
| 1996 | 33.4 | 144 |
| 1995 | 33.9 | 142 |
| 1994 | 34.5 | 140 |
| 1993 | 35.2 | 139 |
| 1992 | 36.2 | 135 |
| 1991 | 36.8 | 136 |
| 1990 | 37 | 132 |
| 1989 | 37 | 129 |
| 1988 | 36.8 | 128 |
| 1987 | 36.6 | 125 |
| 1986 | 36.3 | 124 |