A mass-production plant has eight machines and currently operates two 8-hr shifts per day, 5 days per week, 50 weeks per year. The eight machines produce the same part each at a rate of 15 pc/hr. Determine the annual production capacity of this plant, If the plant were to operate three 8-hr shifts per day, 7 days per week, 52 weeks per year, determine the annual percentage increase in plant capacity.