The Sandy Hook Elementary shooting that killed 27, including 20 children, is already generating the same conversation that every mass shooting in America generates: Why are there so many shootings?

One piece of this puzzle is the national rate of firearm-related murders, which is charted above. The United States has by far the highest per capita rate of all developed countries. According to data compiled by the United Nations, the United States has four times as many gun-related homicides per capita as do Turkey and Switzerland, which are tied for third. The U.S. gun murder rate is about 20 times the average for all other countries on this chart. That means that Americans are 20 times as likely to be killed by a gun than is someone from another developed country.

The above chart measures data for the nations of the Organization for Economic Cooperation and Development, which includes all Western countries plus Turkey, Israel, Chile, Japan, and South Korea. I did not include Mexico, which has about triple the U.S. rate due in large part to the ongoing drug war.

The rate in several developing countries, particularly in Latin America, is significantly higher. Honduras, which has been called the murder capital of the world, has an average firearm murder rate that's about 20 times America's. But make no mistake: For a rich, developed country, the U.S. gun-related homicide rate is very, very high.