" By 1972 the price of a pocket calculator had dropped to $100, and 5 million units were sold. By 1975 the price was down to $25, and sales were doubling every year. In 2014 a Texas Instruments pocket calculator cost $3.62 at Walmart. "

― Walter Isaacson , The Innovators: How a Group of Hackers, Geniuses and Geeks Created the Digital Revolution