From a couple cursory convos with AI chatbots without stratifying by age group of the first node, it looks like the average number of hops in the social network

From a couple cursory convos with AI chatbots without stratifying by age group of the first node, it looks like the average number of hops in the social network would be around 1.7 to 2 hops (just counting those who knew someone killed immediately on 9-11). But the average number of hops probably has a bimodal distribution depending on whether the first person has a lot of people in their social newtwork from either NYC or Washington, DC area.