In every hand to hand combat situation whether they be on the streets, or sanctioned in the ring for MMA or boxing, there will always be more head shots than body shots. The head is a vulnerable spot, and everyone likes to go head hunting. It is ingrained.
However, combat sports such as boxing and MMA has proved body shots as essential for tearing down the opponent, making the head vulnerable, and also able to cause incapacitating pain and damage when a blow is landed on a vulnerable spot. The most well known spot is the liver, and a perfectly landed liver shot has been compared to having your balls stomped on repeatedly. Try toughing that out.