Can "common" people get the sale data from the game companies?

Hey. I'm finally in my 3rd year as a economic student. Now I'm starting to wonder what to write a my final bachelor project.

I have been wondering about the monopoly position of the game(console) companies, mainly the Sony, Microsoft and Nintendo.

The only problem would is the sale numbers of these 3 firms.

Does any1 here (maybe some employees) know places I can get the sale numbers from these 3 places?