Noticing that forty percent of his revenues came from coffee and doughnuts, he started a retail shop that specialized in those products, opening his first coffee and doughnut shop, the "Open Kettle" on Memorial Day in 1948, later renamed "Dunkin' Donuts". Instead of the five different types of doughnuts doughnut shops traditionally offered, Rosenberg offered 52 different varieties. In 1955, upon opening his sixth shop, he decided on the concept of franchising his business as a means of distribution and expansion. In 1959, after the franchise idea had started to catch on, he lobbied at a trade show for the creation of the industry group that became the International Franchise Association in 1960.