I don't have any statistics on hand to back it up, but I feel like education is becoming more widespread. Literacy is increasing in the world. Now anybody in any country (except North Korea?) could get a smartphone and learn almost anything an their one. I think the more educated people are, the less we will have wars. Another very important factor to consider is globalization. We are also more connected than ever to each other. It's much easier to kill somebody that you don't know than to kill your friend. International marriages are definitely becoming much much more common. The more we make friends around the world, the less wars there will be.