Engel coefficient Refers to household expenditure on food expenses. consumption The proportion of total expenditure. Engel, a German statistician, based on his experience data This view is put forward for the change of consumption structure: the smaller the family income is, the greater the proportion of household expenditure or the total expenditure of household expenditure on food purchase. With the increase of family income, the expenditure of household income or household expenditure will be reduced. Engel coefficient is an important index to measure the degree of family wealth.