The linear function $y = -0.6 x + 38$ models the percentage of men in a certain city, $y$, smoking cigarettes $x$ years after 1985. Find the slope for the model. Then describe what this means in terms of the rate of change of male smokers in this city over time.

a) $m =$

b) The percentage of men in this city who smoke has (Enter: increased or decreased or not changed ) at a rate of % per year after 1985.