How much does it cost to raise a gallon of 70 degree water to 140 degree water using a hot water heater?

Are you using wood, coal, oil, electricity , propane, natural gas WHAT is the BTU of the natural gas ( Varies from 900 -1,200 BTU per CU FT) and oil #2 can vary from 138,000 - 140,00 BTU per gallon) and how much are you paying per THERM=Also various countries and cities have different charges for fuel=