March is a bit higher now than Dec. but less history so "Average" is more accurate with Dec. https://www.barchart.com/futures/indices
I can remember seeing ~2.5MM volume and sometimes even up to 5MM... but that was when the price of the SPX was much lower. Perhaps today's "lower volume at higher price" is representative of similar participation... ?? The bid and ask in the DOM are much lower numbers, but at higher prices... was just wondering whether speculation in the ES had made a big move up or down... apparently, neither.
Around 2000 the average volume was 3 million/day. Index was around 1,400. So notional value then was 70K. Now notional value is around 230k. So volume went down, but notional value more than tripled. Margins in 2000 were much lower than today because of notional value changes.