Ten firms compete in a market to sell product X. The total sales of all firms selling the product are $2,500,000. Ranking the firms’ sales from highest to lowest, we find the top four firms’ sales to be $400,000, $325,000, $245,000, and $185,000, respectively. Calculate the four-firm concentration ratio in the market for product X.
Instruction: Round your answer to 2 decimal places.