SPY option expiration chart

I have assembled this chart to graphically display and highlight the close of the SPY on options expiration day. Options expiration is the third Friday over every month. Most charts only show calendar months, but I think this is an effective way to look at market action. The circles have a 2 point diameter, which is roughly the average daily range of the SPY over this time frame. Notice how the market moves around these important dates. Quite often the expiration is a turning point.