| 
  
    | Location | Area (sq. km) | %  change |  
    | 1980 | 1990 | 2000 | 2005 | 2010 |  
    | Asia | 77,690 | 61,960 | 66,270 | 64,660 | 62,880 | -19 |  
    | Africa | 36,700 | 34,140 | 31,780 | 31,020 | 30,270 | -17 |  
    | North  and Central America | 29,510 | 24,160 | 23,100 | 23,420 | 23,870 | -19 |  
    | Oceania | 21,810 | 18,600 | 18,410 | 15,370 | 17,590 | -19 |  
    | South  America | 22,220 | 22,250 | 21,870 | 21,750 | 21,610 | -2.8 |  
    | Total | 189,910 | 161,110 | 161,430 | 156,220 | 156,220 | -18 |  |