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