How many people have killed someone?

I imagine you might find some data about this at the FBI. They collect this kind of data from the police all over the country. You’d find out how many murderers there are and how many people each had killed. As to the military, I’m not sure if the data are available. I’m sure you could find out how many people are estimated killed by American soldiers, but I don’t know if they would tell you how many soldiers had kills.

There are probably similar agencies in other countries that could give you these data. I’m not sure how far afield you want to go. If you are interested in other countries, you could see if the UN has data, and I’ll bet Interpol keeps track of some of this.

It is, of course, impossible to get any reliable data about this. In many war torn areas, no one is tracking anything. People are murdered without anyone else remembering.

I’m afraid that the answer to your question is something you may have to research yourself. It shouldn’t be too hard if you go to the places I suggest, but I’m not going to do this for you. It takes legwork and time I don’t have. You have to supply that yourself, unless there’s someone around here who knows an awful lot more about this subject than I do.

.75%, not counting military actions

It’s a simple process of subtraction to determine the answer. There are now about 7 billion people on Earth. I haven’t killed anyone. That leaves 6,999,999,999 that may have. Contact them, and deduct one for each who, like me, has never killed.

I’d also be interested to see if the population of killers has declined per capita over time, and how killer populations compare cross culturally.

Perhaps this will help

I don’t think many of us would have stats without doing research, but personally, we might know one or so each. I know two people who said they killed (gulp…) and they never went to jail.

@wundayatta This was helpful, but I couldn’t quite get what I needed. There was information on convictions from some US intelligence agencies. And there was information from the UN on mortality rates. Nothing really like an estimate of murderers.

@DrBill Can I ask where you got this from? Also, I’d like to be including military things. Deaths don’t stop counting just because they’re state-sanctioned.

@Qingu That’s another thing I’d like to know. Countries and time periods.

@linguaphile That’s what brought me to think about this. I was re-reading about a chap I knew who killed someone and I was wondering just how common it was.

According to Steven Pinker’s recent book Better Angels of Our Nature, there has been a long term decline in the general rate of violence. I would assume that includes murder.

Let’s bound the problem with an assumption. For every person murdered, there is a murderer, and that mureder is the myurderers only victim. We know this is not true as ther are serial killers but they are small in number.
With that assumption you can look up the murder rate and call the murder rate and you can state the murderer rate is below that value. US murder rate for 2010 is 5 per 100,000 . (You can check for other countries and more details and definitions.) So the murderer rate is below 5 per 100000. That should get you really close.

What if one murderer killed a hundred people. Then your numbers will be skewed.

@Skaggfacemutt Which could explain the second half of my question.

Yes the numbers would be skewed. But, if you look at the number of serial killers you will see they are actually quite few and far between. The assumption I give is the maximum number of murderers possible – one for one. You can decide if that number should be cut in half or not. My gut feeling is the number should be reduced by about 20%, but I have no data.
That would make it 4 murderers per 100,000 people per year in the US

This tells me there are 99996 people per 100,000 who are not murderers per year. Good.

You’re really going to have to limit your data to the last two centuries – that’s the only time frame we were keeping records that would ever be accessible to you. You’re not gonna know how many village murderers there were in Babylon or if there were any Indus Valley serial killers.