The housing sector comprises buyers and sellers of homes. Information on the housing sector encompasses the supply and demand for homes as well as the inventory level of unsold homes. In markets around the country and in different nations, there is a natural progression of demand and supply. In some markets, there are new citizens moving to the city creating demand and, unless there is enough supply to match this demand, prices will rise. Income levels and mortgage rates also play a role in determining how many transactions occur in any given housing market.