Left or Right

Our dog sometimes lifts his left leg and sometimes it's his right leg to relieve himself. He'll even go back and forth trying to determine which is the better leg. I wanted to know if he had a preference. My initial count was 6 left leg lifts and 2 right. This is incomplete data because we walked down the street where there were more things on the left. I'll have to see if there's a preference when I walk a different way.