The chart above is the chart of the Hashprice Index which is developed by Luxor Technologies. This Index shows the revenue of miners that is calculated by the revenue in USD per Terahash per day. Terahash represents the computational power of the mining equipment.
The Hashprice Index Value is diminishing, indicating that miners are suffering the difficult situation of low revenue. There are two common reasons leading to this rigorous situation: the increasing difficulty level of mining activities and the extreme crash of the BTC price.
Regularly, when miners earn less in case of low revenue like the circumstances taking place at present, they tend to shut the mining farm down and this would lead to a decrease in the Hashrate Index Value. In fact, the Hashrate Index is witnessing a very high value, meaning that the vast majority of miners still open the mining engines to mine more BTC despite the low income.