The primary function of the Assessing Office is to accurately estimate the market value of taxable properties within the community. As properties are sold, a record of the sales prices and transaction dates are kept. Later, a market study is conducted to determine the ratios at which comparable properties are being sold in various areas throughout the community. Public Act 206 of 1893, as amended, established the General Property Tax Law under which the Assessing Office operates. Section I of the law states, "… that all property, real and personal, within the jurisdiction of this state, not expressly exempted, shall be subject to taxation."