Por que Engel tem uma curva tão importante quanto a curva de procura?
From the pioneering work of the Prussian economist Ernst Engel in the 1850s onward, a century of household budget studies around the world had demonstrated that food did not account for a fixed percentage of household expenditures — but rather that the share of food in total spending steadily and predictably declined as household income levels increased. In impoverished low-income countries, 60 percent or more of the household budget was allocated for food — while on the other hand, a much smaller fraction of total income went to food in the richest countries in the postwar era
Mais? Vem cá. E note a importância de uma função Cobb-Douglas que você aprende: o que é fixo é o percentual, não o valor, para cada faixa de renda.