(Yicai Global) Oct. 15 -- China's factory gate prices, a key indicator of corporate profitability, fell the most in more than three years last month partly because oil and natural gas extraction costs posted a steep decline.

The producer price index dropped 1.2 percent in September from a year earlier, deepening a decline from August's 0.8 percent dip, according to data the National Bureau of Statistics released today. That's the steepest drop since July 2016.

The gauge has been falling since April and has been in negative territory since July.

The price of oil and gas extraction slumped 13.4 percent, the NBS said.

For the nine-month period ended September, the PPI remained flat from a year ago.

Editor: Ben Armour