Today, thousands of revellers will don their finest green top hats, head to the pub and down a few pints in memory of Ireland’s patron saint.

The dry Irish stout Guinness is often the go-to beer for St Patrick’s Day merrymakers, but its sales have been declining in recent years in the UK and the US.

This is part of a wider trend in Europe and other regions – beer consumption has stagnated or fallen in many countries such as France and Germany, and Asia as a whole drank 1.3% less beer in 2014 compared with 2013 (the most recent data available), according to a report by beer giant Kirin.

Finding the world’s cheapest beer can be a headache since the data varies so much between cities and countries.

Even so, travel planning site GoEuro has compiled a Beer Price Index with 75 of the most affordable and expensive cities for buying beer. For consistency’s sake, it is based on surveys of hotels - you're sure to find pub beers even less pricey in these locales, or even in other cities around the world. Have a look at our infographic to find out where you'll spend the least.