If you've been fortunate to attend any of the six NHL Winter Classic's, you probably noticed a distinct sound. No, not the roar of a sold out football or baseball stadium. No, not a couple of fans getting sick in the corner due to an eventful New Year's Eve. That sound you heard were cash registers in and around the venue going non-stop as fans bought up all sorts of merchandise and concessions.

So it's no surprise to learn that the NHL made bank on the 2014 Winter Classic at Michigan Stadium. Just do the math: 105,491 fans plus highly-priced tickets, plus major ad and merchandise/concession sales equals NHL COO John Collins leaving the game with cartoonish dollar bill signs as eyes.

According to Sports Business Daily's Chris Botta, the Winter Classic this year took in more than $30 million, with the NHL netting a profit over over $20 million.

How much bigger was 2014 than games in the past? Botta explains:

As a point of comparison for those numbers: The previous Winter Classic, the 2012 edition at Citizens Bank Park in Philadelphia, is believed to have made $15 million in revenue against costs of $10 million. Additionally, considering the $30 million in revenue from this year’s Winter Classic: That compares to a typical regular-season game for the NHL’s most successful teams — including Toronto, Chicago, Montreal and the New York Rangers — bringing in between $2 million and $3 million.

Over 8.2 million people in the U.S. and Canada combined watched the Toronto Maple Leafs beat the Detroit Red Wings in the game. That was the largest North American television audience in NHL history.

That sound you just heard? Hockey-related revenue shooting through the roof.

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Sean Leahy is the associate editor for Puck Daddy on Yahoo Sports. Have a tip? Email him at puckdaddyblog@yahoo.com or follow him on Twitter!

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