Unsurprisingly, this thread is rapidly turning into a (e-)book waving thread. But in answer to the OP : there is no answer. You should read because you want to, not because others say that you should. Even at 2.3 per year, you are still ahead of a significant part of the population who haven't read a proper book since they left school - assuming that they read any before they left. Many people do not read as adults except on the beach. This is not wrong, but not right either, because it's individual choice. As a reader myself, I'd rather that you read a week a month at least, but I'm aware that is a rare level of commitment.
And because I like waving my e-peen as much as the next man, I read about a book a week, which is way down on my youth when it was two to three a week. However, I only possess about 450 books.