It is difficult to quantify. And the nature of the books does make a difference.
I put Avid, because I probably do manage 20 books a year. Some of them are short and some are simple. But others are a couple of weeks reading.
And if I were to re-read War and Peace, that would be another 2 months. If I re-read Alice - as I will soon - that is 3-4 days (I read for 40 minutes or so at night mainly).
But I love reading. So Avid seems to fit me.