So after reading the thread of comments, this is one of a few that stuck with me, due to what I think could be incorrect information (I could've also quoted gkk7z, earlier post similar to this one), and that is the average number of levels per perk. Gkk7z, as well as most people assume that the average will be approximately 4, but I do not think this. I think the average is around 2.93 levels/perk, the reasons why are from two sources, one I can link and one I cannot (partially, because it is fairly hard to find outside of a few screenshots on google images search or contacting someone who can p2p it to you). The first inkling that the average levels/perk may be lower came from this interview with Pete Hines, http://www.idigitaltimes.com/fallout-4-gameplay-news-update-270-perks-confirmed-pete-hines-466632, and how when he's talking about raising perks he mentions 70 and then changes it to 270 (likely rounding). I will admit that this isn't much, but it got it into my head that the total number of things to raise while leveling was 275 different things (Perk or Special). There is just something in the way he corrected himself from 70 perks to raise to 270 different options, makes me think he was talking about the whole Perk Chart and not just the Perks (and their specific ranks), but including the Special stats as well. His comment about there being about 270 at the outset also, seems to indicate how many total options available on the perk chart.
The second reason and far more compelling, but also based on the few screenshots I have and my memory of the video, is from the leaked Gamescom footage. In the footage we see that all the Perks and Special stats have stars under their description. Special have ten, where as the Perks range from 1 in VANS to 4 in Gun Nut, we actually don't get any hint that there are any Perks with more than 4 levels. They end up going through the entire Charisma list and the highest confirmed perk level was 3, with only one being 1. This stuck with me particularly, because I was comparing the placement of the stars of the perks to the specials. So for Charisma the average seems, to me, to be 2.9 levels/perk.
This, admittedly hard to back up due to site restrictions, information then leads to why I speculate that the 275 number thrown around includes Specials. See, before with the Pete Hines it was just a little prickle at the back of my neck, something odd I heard in his voice, but after seeing the Gamescom footage it became a decent probability. The reason being is that the number being thrown around is probably based on the total number of stars on the Perk Chart. It's an easy number to count up and is a lot easier than saying that the total number of purchasable things are 275 perks plus 42 additional Special increases. Additionally, if the average was higher then Charisma would have a significantly lower amount of perk levels to buy than most other Specials, thus making Charisma a worse stat to super-charge earlier in the game. At approximately 3 levels/perk Charisma is not as far behind.
Why bring this up, because with the possibility of Cannibalism being a perk with 1 or 2 levels is much more likely if there are an average of 2.9 levels/perk than 3.9.
EDIT: Saw the video again and the upper average of the stars we've seen from the 15 perks that were visible in the Gamescom video was 3.07.