The first person, by timestamp, to comment correctly* on what this graph represents, wins a copy of Black Ice: The Lost History of the Colored Hockey League of the Maritimes, 1895-1925 from The Copper & Blue.
I thought sure Vic would jump on it, so here's a hint: one of the lines is Corsi.
*Copper & Blue Management reserves the right to determine the winner via the exact definition of the graph.