How truthfull should a Non-fiction book be?

I think that in order for a book to be considered as Non-Fiction the book should be about 98% to 100% true. I think that if it is any less than it should not be considered Non-Fiction because if books can be considered Non-Fiction but have a pretty good amount of the book not true then what's the point of having a Fiction, Non-Fiction barrier? Oprah says that it is not right to say that everything in a book is true if it actually isn't true at all. I agree with her because if you say that all of it is true but we find out that some of it really isn't true then you begin to wonder if the rest of the book is a lie also.

I think that we do need to have lines between different genres. I think this because if there aren't lines and you need to use a book for a project you never really know if it is actually true or not. Also if you don't know what genre you are reading you will be really confusing. If I wanted to read a specific genre I would never know which book is that genre because they don't have a label. This is why I believe that David Shields is wrong. I also don't agree with Frey that half-truths are ok. I think that if you call a book a memoir, it should be a memoir not a book with a bunch of half-truths. A memoir is meant to be full of truth and what actually what happened not what sounds best. If a writer wants to make a book that sounds really good then make it Fiction.