Reading the numbers
A pair of tens can be dealt 6 ways and a pair of sixes 6 ways. Once both hands are out, the cards they share leave 36 possible pairings. Each row above stands for every pairing with the same suit pattern. The best case for TT is 81.6%, the worst 80.3%: a shared suit takes away flush cards, and a suit held by both hands can split a flush.
Equity counts half of each tie, so it is the share of the pot TT takes on average if the money goes in now. Compare it with the from the pot odds calculator. For a whole range on each side, use the range equity calculator.