| 时间 | 值 （人/平方公里） | 世界排名 |
|---|---|---|
| 2016 | 53.1 | 141 |
| 2015 | 51.7 | 141 |
| 2014 | 50.2 | 138 |
| 2013 | 48.6 | 139 |
| 2012 | 47 | 142 |
| 2011 | 45.5 | 145 |
| 2010 | 44.1 | 146 |
| 2009 | 42.9 | 147 |
| 2008 | 41.8 | 148 |
| 2007 | 40.8 | 148 |
| 2006 | 39.7 | 149 |
| 2005 | 38.4 | 150 |
| 2004 | 36.9 | 150 |
| 2003 | 35.3 | 151 |
| 2002 | 33.7 | 153 |
| 2001 | 32.1 | 154 |
| 2000 | 30.8 | 157 |
| 1999 | 29.7 | 155 |
| 1998 | 28.9 | 156 |
| 1997 | 28.2 | 155 |
| 1996 | 27.3 | 155 |
| 1995 | 26.2 | 155 |
| 1994 | 24.8 | 154 |
| 1993 | 23.1 | 156 |
| 1992 | 21.4 | 155 |
| 1991 | 19.9 | 159 |
| 1990 | 18.8 | 156 |
| 1989 | 18 | 154 |
| 1988 | 17.7 | 154 |
| 1987 | 17.6 | 154 |
| 1986 | 17.8 | 153 |