UPDATE 1-US year/year import price rise biggest in 26 years

(Adds more detail from report)

WASHINGTON, Aug 13 (Reuters) - 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.

Prices of imported Chinese goods rose 0.9 percent in July. The figure, which tied with the rise for January, marked the largest monthly increase since the Labor Department began tracking Chinese import prices in December 2003. The 12-month gain of 5.3 percent in Chinese import prices was the largest since the index was first published, the department said.

Import prices from Canada were up 29.2 percent on a 12-month basis and those from the European Union 10.4 percent.

U.S. export prices, meanwhile, rose 1.4 percent in July, which was much more than the 0.6 percent that economists had expected.

Prices of agricultural exports increased 6.7 percent and food, feed and beverages exports rose 6.8 percent. Both were the largest monthly gains since the Labor Department began tracking the prices in December 1988. (Reporting by Doug Palmer, Editing by Chizu Nomiyama)