1. Except as otherwise provided, an assessment at the rate of three cents per hundredweight [45.36 kilograms] is imposed upon all potatoes grown in this state or sold to a designated handler.

2. The council may increase the assessment by no more than one-half cent per hundredweight [45.36 kilograms] annually until a maximum assessment of four cents per hundredweight [45.36 kilograms] is reached.

3. This assessment is not imposed on any potatoes retained by producers for seed or for consumption by the producer, the producer's family, and nonpaying guests.