Apple does not provide much information about how many users actually accept / reject push notifications, but you can get an idea of what is happening by comparing the number of common settings and the number of valid push token tokens that you have (I assume that , since you are interested in analytics, you already have a Push server setup) Push notification tokens are generated only if the user accepts.
If you need more information about the actual push notifications, you will need to get your hands dirty and actually add the tracking code to the application. If you're looking for something free, try Google Analytics for iOS with custom event tracking: https://developers.google.com/analytics/devguides/collection/ios/v2/events
Urban Airship , : http://urbanairship.com/products/push-messaging#analyze