Business Insider found the difference between Zuckerberg's 2017 and 2018 net worths (as provided by the Forbes' 2017 and 2018 richest people in the world lists, published every March) to determine his annual earnings. Zuckerberg's annual earnings came to roughly $15 billion.
We then divided all annual earnings by 8,760, the number of hours in a year, to calculate how much he earned an hour.