In the mid-18th century, gin became extremely popular as it was much cheaper to buy than beer. This was known as the 'gin epidemic'. By 1740, six times more gin than beer was being produced, and of the 15,000 drinking establishments in London, half were gin-shops. The Gin Act 1736 imposed a prohibitively high duty on gin, but this caused rioting, and so the duty was gradually reduced and then abolished in 1742. The Gin Act 1751 was more successful: instead of a tax it restricted gin producers to selling only to licensed premises.