Based on the following data, calculate gross domestic product (GDP), net domestic product (NDP), national income (NI), personal income (PI), and disposable personal income (DPI): Gross private domestic investment $180 Interest paid to consumers $9 Contributions for social security $25 Personal consumption expenditures $600 Transfer payments $60 Dividends $15 Indirect business taxes $75 Exports $25 Depreciation $60 Government purchases of goods and services $175 Corporate income tax $70 Imports $20 Personal tax payments $90