Green's Custom Drives, Inc. is a professional cement manufacturer and are trying to determine their contribution margin. Green's is providing the following information.

Tons of cement produced and sold Sales revenue Variable manufacturing expense Fixed manufacturing expense Variable selling and administrative expense Fixed selling and administrative expense Net operating income 270,000 $974,000 $231,000 $310,000 $ 158,600 $ 92,000 $ 182,400 Based on this data, Green's contribution margin ratio is closest to