A new survey by Credit Suisse has found that 63% of U.S.-based iPhone customers would stay with AT&T if/when their exclusivity deal with Apple expires. Business Insider reports that of the 37% who say they would leave the carrier, 23% would jump to Verizon, 3% would go to Sprint, and 2% would go to T-Mobile, with 9% said they weren’t sure. When broken down further, 26% said they would stay with AT&T if they improve their network,…