I do wonder if electric cars paid a tax equivalent to the gas tax what would the cost be? Has anyone done the calculation? If a gallon of gas gets and average

I do wonder if electric cars paid a tax equivalent to the gas tax what would the cost be? Has anyone done the calculation? If a gallon of gas gets and average of X miles across all cars then how much electricity is that to tax the same amount? I'd be curious since I have strong privacy and persecution of poor people objections to a mileage tax.