Question: when administrative centre is Egilsstaðir, what is the pop./ km²?
SQL: SELECT COUNT("Pop./ km²") FROM "1-2252745-1" WHERE "Administrative centre" = 'Egilsstaðir';

Question: when the name is Southern Region, what is the administrative centre?
SQL: SELECT "Administrative centre" FROM "1-2252745-1" WHERE "Name (English)" = 'Southern Region';

Question: when the area (km²) is 22721, what is the pop./ km²?
SQL: SELECT "Pop./ km²" FROM "1-2252745-1" WHERE "Area (km²)" = 22721.0;

Question: What is the max pop of 2008 for Selfoss?
SQL: SELECT MAX("Population 2008-07-01") FROM "1-2252745-1" WHERE "Administrative centre" = 'Selfoss';

Question: When the # is 4, what is the pop./ km²?
SQL: SELECT "Pop./ km²" FROM "1-2252745-1" WHERE "#" = 4.0;