estimated tax payments are then divided by net income ie gross earnings minus personal income tax and employees social security contributions plus family benefits for instance food water supply medical care and public transport are often granted reduced rates or exemptions this approach typically implies a considerable deadweight loss and people at higher income levels often benefit more in absolute terms since they consume more in the case of mexico the total implicit subsidy due to the zerorating of food was estimated at some of gdp in the mid s dalsgaard