Can I deduct half of my rental expenses (i.e. taxes, insurance premiums, mortage interest) if I rented out a room of my home to a friend?

I bought a house last year and rented out one of the three rooms to a friend the entire time I owned the house. I was in the master bedroom and one room remained empty that we both used to store things in. We both equally shared all other areas of the house (kitchen, living room, garage, etc.). Other guidelines/articles I read about deducting rental expenses say that you should allocate them according to how much of the home you rented, using a 'logical method', the top two methods being by square feet or by number of rooms rented. I only rented one room and charged a fair rate for the room, however we effectually shared the entire house (with the exception of our individual rooms). Should I deduct half of my expenses since we effectively split the house equally, or should I only deduct a third of those expenses because I only rented out one of three rooms?