Historical spread data
How each broker's spread has moved by session and over time, per instrument and account type, from the same observations the real-time table is built on.
Not enough compatible data is available to publish historical spreads.
Historical spreads are built from the live observations once the pricing feed is connected; each series carries its instrument, account, session, observation count and the dates it covers. Until then the lowest-spread ranking orders brokers by the typical spread each publishes.