What does the numbers for the S&P mean in the image below? For example, on 18th October, it says S&P -5.60. What does the -5.60 mean? I looked at the S&P Open, High, Low and Close prices for the S&P Index, but I don't know where the -5.60 comes from.
What does USB, and the numbers associated with it mean?
http://www.google.com/finance/historical?q=INDEXSP%3A.INX&ei=aAuBUJjKOMiekAXR_wE
(I got the chart from the site dailyspeculations.com)