Last year, 3 1/2 acres of strawberry fields produced approximately 14,700 pounds of strawberries. This year the number of acres planted with strawberries is increased to 5 acres. Use proportional reasoning to estimate the farm’s income from the sale of the strawberries.

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.