The total cost of ground transportation for Canadian shippers dropped for the third month in a row, according to data from the Canadian General Freight Index.

Ground transportation costs dropped 0.4 percent in April, dropped again by 1.2 percent in May and slipped by 1.8 percent in June.

"The decline from March to June of this year follows the same pattern as March to June of 2013, however this year the decline is not as steep," said Doug Payne, president of Nulogx. "Total costs of freight are 6.1 percent above last year at this time."

The base rate index, which excludes the impact of accessorial charges, dropped 1.4 percent in June when compared to May.

But average fuel surcharges rose in June2014. Fuel was 21.57 percent of base rates in June versus 21.37 percent in May.