The cost of goods and services increased 0.6% from August to September and 3.7% compared to the same time last year, the Bureau of Labor Statistics reported Wednesday.

Economists surveyed by Dow Jones expected gains of 0.6% and 3.6%, respectively, according to CNBC.

Annualized inflation was 3.4% in September.

The price of gasoline increased 9.1% in September, contributing largely to the overall index increase, the BLS report shows. 

The CPI report was the last before the Nov 3 midterm elections, in which "affordability" is a major issue for voters.