A certain smelting plant operates 24 hours per day, with three shifts of 200 workers per shift. Due to a flu epidemic, 1/4 of the workers on the first shift, 10 percent of the workers on the second shift, and 100 of the workers on the third shift are unable to work on a given day. If each worker and each shift has the same productivity, what is the approximate percent decrease in productivity due to the flu epidemic?