In the 20th century, the province of Québec underwent deep social changes, communally known as the Quiet Revolution
. The parents of the boomers were very religious, but the boomer themselves refused the message of Christianity, and their children almost entirely atheists. That's the official story, and it matches my social experience.
Depending on the actual numbers, this might make Québec the least religious nation in the Americas, and one of the least religious in the world. Except, I have never been able to find the actual numbers. How many Quebecers are: practicing Christian, baptized but not practicing, religious but not necessarily Christian, spiritual but not in an organized way, and atheists? How do these numbers compare with the rest of the world?
The only statistics I was able to find for Québec specifically (as opposed to Canada as an aggregate) said 83% were Christian, which just cannot be accurate. It is probably the percentage of people baptized, independently of whether they are actual believers. After all, I and my parents might be a staunch atheists, but I was still baptized to please my grandmother.