BEIJING, May 11 -- China's producer price index (PPI), which measures costs for goods at the factory gate, was down 3.6 percent year on year in April, the National Bureau of Statistics said Thursday.

The decrease expanded by 1.1 percentage points from that registered in March. On a monthly basis, China's PPI edged down 0.5 percent, according to the bureau.

Affected by the fluctuation of international commodity prices, weak demand in domestic and foreign markets and the high comparison base during the same period last year, the PPI declined, said the bureau's chief statistician Dong Lijuan.

The PPI for the oil and gas extraction industry dropped 16.3 percent year on year, and that of the non-ferrous metal smelting and pressing industry fell 8.6 percent from the same period last year.

Meanwhile, the PPI of the agricultural and sideline food processing industry rose 1.1 percent year on year, while that of computer communications and other electronic equipment manufacturing industries declined 0.7 percent year on year.

The carry-over effect of last year's price movements contributed about 2.6 percentage points to the year-on-year PPI decline in April, Dong said.

Thursday's data also showed that China's consumer price index, a main gauge of inflation, edged up 0.1 percent year on year in April.