Balance of trade in an open economy.
An open economy has the following pattern of income and domestic expenditure:
| Variable / Year |
Year 1 (£) |
Year 2 (£) |
Year 3 (£) |
| National income |
500 |
250 |
200 |
| Government expenditure |
200 |
250 |
200 |
| Private consumption |
250 |
300 |
250 |
| Investment |
50 |
200 |
200 |
For each of the three years, show the balance of trade facing the economy.