In Canada, fewer than 5% of households had a microwave oven in 1979, but more than 88% of households owned one by 1998. But during the time when microwaves became ubiquitous in Canadian homes, there was a steep learning curve for customers. They could not leave metal objects in a microwave like they could have with ovens; making for some rather harrowing moments as the newbie microwave user watched with concern over sparks and loud noises emanating from the microwave when a utensil was left in a bowl to be heated. This is an example of what characteristic of the rate of adoption in the diffusion of innovation: comparative experience compatibility relative advantage complexity