A retail store had sales of $46,000 in April and $55,800 in May. The store employs eight full-time workers who work a 40-hour week. In April the store also had six part-time workers at 9 hours per week, and in May the store had seven part-timers at 13 hours per week (assume four weeks in each month).
Using sales dollars as the measure of output, what is the percentage change in productivity (dollars output per labor hour) from April to May? (Round your intermediate calculations and final answer to 2 decimal places.)
Change in productivity ( ) %