It's a bit duplicitous to count the full 53 man roster. In the AFC there are 26 starting positions open for MLBs (not everyone runs a 3-4). The first 2 players selected represent the top 7.5%. When we bring the 2 alternates, it jumps to 15% and that's getting a little watered down.
Of course, it's just a popularity contest and with the rise of IDP in fantasy football, fans just check the top boxes. Of course, the players love voting for the UFAs as well.