The mass shooting at the Washington Navy Yard yesterday is the fifth mass shooting in the United States this year, and the latest in an epidemic of such gun violence over the last three decades.

The FBI doesn’t specifically define mass shooting. However, it identifies an individual as a mass murderer—versus a spree killer or a serial killer—if he kills four or more people in a single incident (not including himself), typically in a single location.

Using the above definition, there have been 6 mass shootings over the past nine months and at least 62 mass shootings in 30 states since 1982. Twenty-five of these mass shootings have occurred since 2006, and 7 of them took place in 2012.

What industrialized nation in the world would put up with this epidemic of violence without doing something besides wringing our hands? The answer, of course, is only one, the USA.

Mass shootings have occurred in Germany, Norway, Finland, Canada, Australia, and the United Kingdom over the last two decades, but not at nearly the rate as the United States.

So what is the difference?

According to the latest Small Arms Survey conducted in 2007 by the Graduate Institute of International and Development Studies in Geneva, there are far more guns in private hands in the USA than in any other country. On average, the survey reported 88.8 guns per 100 people in the USA, compared with 54.8 per 100 residents in Yemen and 45.7 per 100 in Switzerland.

Peter Squires of the University of Brighton in the United Kingdom, who has studied mass shootings in Europe and the United States, found that European countries tend to have more tight-knit societies where a strong social bond supports people through crises.

I don’t know if our country can ever replicate the social bonding that occurs in European countries, but it’s way past time for the politicians of this country to quit pandering to the gun lobby and to do SOMETHING to stem the tide of violence.