Own Bitcoin node sync status, historical hashrate, SegWit adoption, and mining pool distribution — data verified directly from the blockchain.
Estimated from difficulty and actual inter-block time at each difficulty adjustment (every 2016 blocks).
% of SegWit transactions per block, sampled at each difficulty adjustment (via getblockstats).
One block sampled per difficulty epoch, identifying the pool by the coinbase label. Not an exact hashrate share — a point-in-time sample repeated over time, useful for spotting concentration trends.