For taxation purposes, property is usually assessed at a fractional part of its sale (market) value. Revenues are determined by applying tax rates against these assessed values. Since states use different percentages of sale value in calculating assessed value, comparisons between states require the determination of sale values and true tax rates. Thus, if property valued at $ 100,000 and assessed at $40,000 has a tax rate (sometimes called apparent tax rate) of 40 mills, it would have a true tax rate of 16mills. If the assessed value of a piece of property is 25 percent of its sale value, its true tax rate is what percent of its apparent tax rate?