The fur industry in Canada had undergone almost consistent gradual expansion since its inception, and rising prices following the First World War spurred even greater growth. Native hunters and trappers, particularly in the North, benefited from these higher prices but also found competition for ever-scarcer fur resources increasing as more non-Natives entered the industry. The long-standing system of trading furs for goods such as household items, firearms, ammunition, and traps was replaced in this period by a monetary system in which traders purchased furs with currency and the trappers bought their needed items. The sudden collapse of prices for furs in April 1920, hit the trappers of the North particularly hard, as communication problems resulting from distance and general isolation meant that few trappers were aware of the sudden devaluation of their product prior to coming in to the trading centres to barter their furs. As a result of the price collapse, many smaller trading companies were unable to remain financially solvent, and their disappearance left the Hudson's Bay Company with a virtual monopoly over trade in much of the North once again.