3. Suppose the country of Macroland's annual fiscal standing for six recent years. Assume that interest payments on the debt are covered by government expenditures and that budget surpluses are used to retire the debt. (Amounts are in billions of dollars) Year Government Tax revenues expenditure Deficit (-) or Surplus (+) 1 1800 1800 Debt 0 2 1180 1780 3 2280 -1500 4 2100 500 S 2400 +100 6 2500 2600 a. Calculate the missing data b. What factors might affect government expenditures and tax receipts from year to year?