The Sandy Hook Elementary School massacre in Connecticut almost three years ago did nothing to restrict access to guns, as the students of Umpqua Community College in Oregon learned to their cost yesterday.

But it did a huge amount for the National Rifle Association.

As the rest of America mourns yet another murderous gun spree on campus, a review of financial filings shows just how far the mammoth gun organization has been able to cash in, big time, on the fallout that followed Sandy Hook in December 2012.

Membership dues jumped as supporters rallied to the cause. So did profits. And executive pay ran into the millions. Not bad for a charity that is exempt from taxes.

Yesterday’s college slaughter in Oregon, which left at least 10 dead, was the 142nd shooting incident in a school or college since Sandy Hook. As there have been only over 1,000 days during that period, this means there’s been a shooting in an American school or college about once a week. In most of those, at least one person was injured, and in about one incident a month, at least one person was killed.

So can we all stop claiming we’re “shocked” when it happens yet again? A murderous rampage on an American school or college campus happens about as often as you get a bill from your mortgage lender.

“ The debate about gun control has produced no concrete action. But it has shaken up gun supporters, who have rushed out to buy more weapons and sent more money to the NRA. ”

In total, about 10,000 Americans are murdered with guns each year, or more than three times the number of people killed on 9/11. It’s equivalent to lining up and shooting three baseball teams each day. That doesn’t include suicides.

It’s not especially remarkable. Almost nothing makes it as easy for a crazy person to kill a lot of people as a gun. Especially a semi-automatic handgun. Yet, apparently, we have become resigned to the situation.

There was a brief flurry of interest in gun control in late 2012 and early 2013, after Adam Lanza had shot and killed 26 people, including 20 children, at the Sandy Hook Elementary School in Newtown, Conn.

A few politicians even pretended in public that they wanted to do something. Stocks in gun manufacturers briefly tumbled on Wall Street.

The debate about gun control produced no concrete action. But it did shake up gun supporters, who rushed out to buy more weapons and sent more money to the NRA. They were already in a panic after President Obama got re-elected.

Gun makers such as Sturm, Ruger RGR, +4.15% and Smith & Wesson US:SWHC saw a surge in sales.

Oregon shooting suspect's father shocked

NRA Chief Executive Officer Wayne LaPierre proved a master of the situation. He ignored any calls for compromise or common sense. Instead he made a speech demanding armed guards in every school in the country, a speech that was effectively a joke told with a straight face.

The most fanatical gun supporters saw the incident as a call to arms — literally.

NRA membership dues skyrocketed by a staggering 62% in the year after Sandy Hook, from $108 million to $176 million. Total revenue in 2013 hit a third of a billion dollars.

As a result, the massive organization saw profits — excuse me, “surpluses” — rocket 2,750% to $57 million.

Of course, that’s before taxes. But, then, it didn’t pay any taxes, for it is a nonprofit charity.

The NRA estimates it was also helped by 150,000 volunteers. How many corporations could boast as much?

The NRA top executives shared that year in a treasure chest of more than $8 million in salary, bonuses, nontaxable benefits, deferred pay and other compensation — a nice payout for an organization that enjoys charitable exemption from U.S. taxes. LaPierre alone made a million bucks a year, which is, ironically, equal to about $100 for every man, woman and child murdered with a gun in America.