To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
Every time my niece comes round (she's only 4 - but can read) she asks for my kindle and she reads this book. It takes her about an hour but she reads them over and over again. Thank you for giving my niece something to do :-)