Table: rural_municipalities_saskatchewan
Columns: rural_municipality_rm
rm_no
sarm_div_no
census_div_no
population_2011
population_2006
change
land_area_km
population_density_per_km

Question: What is the average change to have a land area of 546.74 and a population density greater than 0.5?
SQL: SELECT AVG("change") FROM rural_municipalities_saskatchewan WHERE "land_area_km" = 546.74 AND "population_density_per_km" > 0.5