CALGARY -- A new study says home prices climbed in all major Canadian cities in May except Calgary, which suffered its biggest one-month drop in at least a decade and a half.

The study, the Teranet--National Bank National Composite House Price Index, found that Calgary home prices dropped 3.3 per cent from April. That was the largest monthly drop since the index was created in 1999.

Nationally, prices were up 0.9 per cent from the previous month, with the Calgary figures cutting the average by 0.3 per cent.

Year over year Calgary's home prices showed a 1.4 per cent drop, according to the index.

Calgary's home prices have been hit by a slower economy as oil prices remain low.

Only homes that have been sold at least twice are considered in the calculation of the Teranet Index, which uses data from public land registries in 11 major Canadian markets coast to coast.