CREATE TABLE "northern_hamlets" (
  "name" text,
  "population_2011" real,
  "population_2006" text,
  "change_pct" text,
  "land_area_km" text,
  "population_density_per_km" text
);

Question: What is the population density (per km) that has -6.7 as the change (%)?
SQL: SELECT "population_density_per_km" FROM "northern_hamlets" WHERE "change_pct"='-6.7';

Question: What population density (per km) that has 84 as the population (2006)?
SQL: SELECT "population_density_per_km" FROM "northern_hamlets" WHERE "population_2006"='84';