The large majority of U.S.-based iPhone users are happy with AT&T, according to a new study by the Yankee Group. CNNMoney reports that 73% of iPhone users are “very satisfied” with AT&T, a number that compares favorably to how non-iPhone smartphone users feel about AT&T. The survey found the satisfaction rate of AT&T subscribers as a whole is 68%, while AT&T smartphone users were only slightly more satisfied at 69%. Analysts with the Yankee Group attributed the high iPhone numbers to a “halo effect.” “Consumers transfer the high gloss of their Apple iPhone experience to AT&T,” Carl Howe, Yankee Group analyst. “The iPhone creates a halo effect that rubs off.” Overall, the study estimates that the iPhone will be worth $1.8 billion in sales to AT&T this year, and will generate $9 billion for the company over the next five years.