A firm currently sells its product at a price of $8 per unit, and generates sales revenue of $7,200 per day. The firm's management team decided to increase the price of the product to $8.40 but following this increase sales revenues fell to $7,106.40 per day. What is the price elasticity of demand of the product? (Use the simple point method for calculating price elasticity of demand. Give your answer to 1 decimal place. Ignore a minus sign.) ____.