With the exception of the April figure, the rate of inflation as measured by the Consumer Prices Index has fallen each month since Autumn 2013.
Falls in transport services costs, notably air fares, were the largest reason behind the reduction in the rate.
Other large downward effects came from the food and non-alcoholic drinks and clothing sectors.
Price movements for motor fuels stopped the rate of inflation falling further. Average petrol and diesel prices rose slightly between April and May this year but each fell by over 3 pence a litre a year ago.
CPIH, the measure of household inflation which includes the costs faced by owner occupiers, grew by 1.4% in the year to May, down from 1.6% in April.
Ian Stewart, chief economist at Deloitte said:
“The UK is experiencing low inflation and strong growth, the holy grail for economic policymakers. Inflation has almost halved from last year’s peak and growth expectations for this year have almost doubled. We are in the sweet spot of the economic cycle.”