The decline in smoking started well before 20 years ago, smoking rates used to be like 50% of the adult population, now it's down to 10%ish.

However, based on online graphs, it seems like it has been closer to 50% over the last 20 years.

https://uwaterloo.ca/tobacco-use-canada/adult-tobacco-use/smoking-canada/historical-trends-smoking-prevalence https://www.macrotrends.net/global-metrics/countries/can/canada/smoking-rate-statistics