Then usable tread depth is compared to remaining tread depth in order to calculate tread wear percentages. For example, a tire that started with 10/32 of original tread depth and has worn off 4/32 (down to 6/32 of remaining tread depth) is 50% worn.
1 If you know the census tract number: Use the IRS list of 2014 Qualified Census Tracts by county. 2  If you have a street address: Visit HUD's interactive QCT Map and enter the property address to view what Census Tract the property is located.
Computing Population Density. To determine an area's population density, you just have to divide an area's total population by the land area in square miles (or square kilometers). For example, Canada's population of 33 million, divided by the land area of 3,559,294 square miles yields a density of 9.27 people per square mile.