Average transaction fees on the Ethereum network are decreasing. This means lower user activity and slower growth in the DeFi industry.The average cost of confirming a transaction in Ethereum has hit its lowest level since mid-July when the decentralized finance (DeFi) boom was just beginning. Lower fees mean fewer transactions take place on the Ethereum blockchain.According to BitInfoCharts, the average transaction fee on the Ethereum network reached $ 0.9 on Saturday, and $ 1.02 on Sunday. Recall that in early September this indicator reached $ 14.58. In the first month of autumn, ETH miners earned $ 166 million in fees — a record amount in the entire history of Ethereum.Screenshot: BitInfoChartsThe boom in the DeFi market has been a major driver of miner revenue growth. However, Ethereum transaction fees were down 86.2% in early October from the September highs. At the same time, in the first week of October, the hash rate of the Ethereum network reached an all-time high of 250 Tx / s amid growth in DeFi.Screenshot: BitInfoChartsThe decrease in fees may be attributed to the slowdown in the growth of the DeFi industry. According to DeFi Pulse, the dollar value of DeFi-locked crypto assets has hovered above $ 11 billion since late September. At the same time, in the previous months, this indicator grew extremely rapidly. In February, it exceeded $ 1 billion for the first time, in June — $ 2 billion, and then surged upward, reaching $ 3 billion in July, $ 7 billion in August, and a peak of $ 13.2 billion in September.