Suppose that in an economy, 100 worker-hours produce 160 units of output in year 1. In year 2, worker-hours are 120 and output is 216. In year 3, worker-hours are 130 and output is 260. Using year 2 as the base year, calculate the following:

a.) Productivity growth from year 1 to year 2

b.) Productivity growth from year 2 to year 3