Calculate percentage annual growth rates using the data that follow. (a) Productivity growth measures increase in output per hour of work. Output per hour was 54.0 in the first quarter of 1973, 75.4 in the first quarter of 1996, and 111.0 in the first quarter of 2010 (2005 = 100). Calculate the average annual rates of productivity growth between 1973 and 1996 and between 1996 and 2010. Using your answers, explain during which of these two periods living standards rose more quickly.