According to Information Resources International, in 1993, Doritos earned $1.2 billion in retail sales, one-third of the total Frito-Lay sales for the year. Nevertheless, in the costliest redesign in Frito-Lay history, in 1994 the company spent $50 million to redesign Doritos to make the chips 20% larger, 15% thinner, and rounded the edges of the chip. Roger J. Berdusco, the vice president of tortilla chip marketing, said a primary reason for the change was "greater competition from restaurant-style tortilla chips, that are larger and more strongly seasoned". The design change was the result of a two-year market research study that involved 5,000 chip eaters. The new design gave each chip rounded corners, making it easier to eat and reducing the scrap resulting from broken corners. Each chip was also given more seasoning, resulting in a stronger flavor. The redesigned chips were released in four flavors beginning in January 1995.