Future dmg costs are based on the projected increases in per capita dmg expenses for the total U.S. population from the NHE accounts. Changes in the three determinants of expenditures - that is the number of people enrolled in the programme, the quantity and intensity of services each person uses, and the price for each unit of service -are then projected for future years. The structure of the NHE Projection Model is a multi-equation structural econometric model that is estimated based on the historical NHE data.