Michaels Lobster Food Truck has been operating for three years, but hes yet to make a profit in the competitive food truck industry. Last year, he sold 2,500 items at an average price of $12. It costs him $9 to cover his ingredients for each item, and he also has fixed costs of $8,000 per year to cover for his truck, marketing, insurance, etc. What percentage increase in the number of units sold is required for Michael to break even?