WASHINGTON -- U.S. import prices climbed a bigger-than-expected 1.7 percent in July, capping a 21.6 percent gain over the past 12 months that was the largest in the past 26 years, a Labor Department report showed on Wednesday.

Import prices for petroleum products, including crude oil, rose 4.0 percent in July and were up 79.2 percent over the past 12 months.

Economists polled ahead of the report were expecting overall import prices to rise 1.0 percent in July, when oil prices set a record above $147 per barrel. Since then, oil has fallen sharply and a big U.S. corn crop has pushed farm commodity prices lower.

Import prices for non-petroleum products increased 0.9 percent in July and 8.0 percent over the past 12 months, the largest such gain since the period between June 1987 and June 1988.