All Time High is the historical maximum of the cryptocurrency price.
Bitcoin's ATH was installed on December 16, 2017, when 1 BTC cost $19,665.
One and a half years after that, the price of the first cryptocurrency fell by 73%. However, this is still not so bad; the fall records sometimes exceed 99% (for example, Bytecoin #BCN, Bitcoin Diamond #BCD or VeChain #VET). Stablecoins show the smallest drop: for example, the famous Tether (the average price difference with ATH is 25%) or USD Coin #USDC — 12%. Particular services track ATHs of various cryptocurrencies.