Housing conditions and energy efficiency Households by main heating source by income quintile per unit of consumption. Unidades: NA ;Electricity;Gas;Diesel;Other;Does not use any heating system;Not specified; Total;32,1;35,8;8,9;6,5;15,7;1,1; First quintile;34,1;25,4;6,7;7,2;25,5;1,2; Second quintile;33,5;29,4;8,7;7,4;20,3;0,7; Third quintile;33,2;34,5;8,5;6,8;16,3;0,8; Fourth quintile;33,4;39,8;9,5;6,4;9,7;1,3; Fifth quintile;26,7;49,6;10,8;4,6;7;1,3; Notas: Income per unit of consumption is obtained, for each household, by dividing total household income by the number of units of consumption. The distribution of persons is taken. Fuente: Instituto Nacional de Estadística