Toyota provides an option of a sunroof and side airbag package for its Corolla model. This package costs $1400. Assume that prior to offering this option package, Toyota wants to determine the percentage of Corolla buyers who would pay $1400 extra for the sunroof and side airbags. How many Corolla buyers must be surveyed if we want to be 95% confident that the sample percentage is within four percentage points of the true percent all Corolla buyers?