it's within 200 miles. Also a different but fun fact - 80% of the canadian population lives in one straight line between Quebec City and Windsor Ontario (adjacent to Detroit), we call that l'axe Quebec-Windsor: https://en.wikipedia.org/wiki/Quebec_City–Windsor_Corridor
The Wikipedia article you linked to says it's actually closer to 50%.
Quote: "With more than 18 million people, it contains about half of the country's population"