Ethereum's supply on exchanges has dropped to a record low of 4.9% as investors continue to withdraw ETH.On-chain data reveals a downtrend in the supply on exchanges for Ethereum, indicating bullish sentiment among investors.The long-term trend shows a decrease in Ethereum supply on exchanges, with temporary deviations observed during profitable opportunities.In comparison, Bitcoin has also seen a net outflow trend from exchanges, with 1.7 million BTC withdrawn in the past five years.