What it shows is where the majority of spins occur.
I certainly hope not. Because that would indicate that for each and every spin I deliberately enter as part of my aerobatic sequence (initiated at 3500', recovered at 2500'), at least four spins take place below 250' and are most likely fatal.
I would hope that the chart shows "unintentional spins in general" or "unintentional spins leading to an accident/incident" or maybe even "unintentional spins leading to at least fatality". And even then there's a distinct difference between the three possibilities wrt. this discussion.
So could anyone provide a link to the original article from the FAA so that the graph can be interpreted properly?