Nate Silver of the New York Times wrote a great piece about hockey recently that starts with the question of why Canadian NHL teams haven't won the Stanley Cup in the last two decades. One reason is simply that there aren't that many Canadian teams anymore, with various franchises having relocated from the Great White North to the southern and western United States. Silver, by estimating the approximate number of hockey fans in various markets, makes a strong case that the NHL would be better off financially to abandon its American expansion and return to being a more strongly Canadian league. Below is a visualization of his recommendations.
There's a lot more interesting stuff in the article; read it here.