Stock Index historical closing prices

I'm trying to get end of month closing prices for the SP500 index automatically and put them into a table updated each month. Is there anyway to accomplish this using the STOCKHISTORY function? I can set a cell as a STOCK data type and get the price for the index, but cannot get historical prices sequentially to put in a table. Yahoo Finance now no longer allows downloading of historical data for SP500 (^GSPC) for some reason.

Thanks!