The table below shows government purchases (G), net tax revenues (T), and debt-service payments (interest payments) over a 4-year period for a hypothetical economy. All figures are in billions of dollars. Assume the stock of debt at the end of 2015 is $500 billion. Year G T iD Stock of Debt 2015 250 260 18 500 2016 250 262 18 2017 265 263 20 2018 270 267 21 TABLE 31-1 What is the balance of the budget in 2016? Is it a deficit or a surplus? Show your calculations. What is the primary budget's balance in 2016? Is it in deficit or in surplus? Show your calculations