Economists had expected a 28% increase.
Prices for manufacturing products increased 24.6% yearly in May and those for mining and quarrying rose 34.0%. Prices for water supply gained 5.3% and those for electricity, gas, steam and air conditioning surged 45.8%.
Among the main industrial groupings, cost in the energy sector grew 53.9% and those for intermediate goods increased 29.7%.
On a monthly comparison basis, producer prices increased 1.9% in May.