The given graph illustrates the proportion of houses used electricity or gases before 1950 to 2010.
Overall, while natural gas witnessed a steady drop, electricity tended to rise up throughout years.
Before 1950, most houses, particularly 60% of homes chose natural gas as their heating fuel. This rate remained the same to the end of the 1960s. At the dawn of the 70s to the end of the 80s, natural gas showed a considerably decline as 45% houses chose this fuel to heat. This percentage stood still to the beginning of the 21st century.
Electricity was unpopular at its starting point, with only 15% of houses used this energy to heat before 1950. In the following years, electricity experienced a steady rise as natural gas began to decline. In the dawn of 21st century, electricity reached its peak as the same levels of gas, with 45% houses consumed this energy for heating.