For its three investment centers, Gerrard Company accumulates the following data: I II III Sales $1,946,000 $4,012,000 $3,903,000 Controllable margin 1,002,800 2,177,010 3,628,800 Average operating assets 5,014,000 8,063,000 12,096,000 Compute the return on investment (ROI) for each center.