Moderately long preface before my answer---for a good reason.
I can read very quickly. (My sister-in-law once saw me open a card from her sister, my wife, close it immediately and laugh. She said that I could not possibly have read what the card said and what my wife had written and respond. My wife simply said, "oh, yes, he did." and I simply quoted what the card said and summarized my wife's personal comment.) My point---When I say I can read very quickly, trust me.
Reading and eating have this similarity---occasionally you eat over a relaxing 2 hour period and occasionally you "slam" down a quick protein shake because you are in a hurry. My point---the actual speed you read something at will depend on the material and personal factors and goals at the time you choose to read.
Reading much faster than you currently do is a worthwhile and usually attainable ability.