How many books a human can read, understand, tokenize, memorize in 15 minutes, 15 days, 15 months, 15 years? What's the rate of forgetting for the ingested mat

How many books a human can read, understand, tokenize, memorize in 15 minutes, 15 days, 15 months, 15 years? What's the rate of forgetting for the ingested material for human brain?