The units system of alcohol is made up nonsense - check out QI on You Tube below:
In Britain, 21 units of alcohol per week is the recommended allowance, but in Poland it is 12.5, in Canada 23.75, in the USA 24.5, in Denmark and South Africa 31.5 and in Australia 35. However, if you drink between 21-30 units, you belong to a group of people who have lowest mortality rate in Britain. You actually have to consume 63 units per week, or one bottle of wine a day, to have the same death risk as a teetotaller. The man who invented the system admitted the number was made up.