Assertion: region's center | /r/AtLocation | polk county
Facets:
value: since the 1960 census
type: TEMPORAL
Source sentences:
text: The center of population has moved less than 5 miles (8 km) to the east and approximately 1 mile (1.6 km) to the north between 1980 and 2010 and has been located in Polk County since the 1960 census.