List of countries by GDP (nominal)
Gross domestic product (GDP) is the market value of all final goods and services from a nation in a given year. Countries are sorted by nominal GDP estimates from financial and statistical institutions, which are calculated at market or government official exchange rates. Nominal GDP does not take into account differences in the cost of living in different countries, and the results can vary greatly from one year to another based on fluctuations in the exchange rates of the country's currency. Such fluctuations may change a country's ranking from one year to the next, even though they often make little or no difference in the standard of living of its population.
Debt-to-GDP ratio
By dimensional analysis these quantities are the ratio of a stock (with dimensions of currency) by a flow (with dimensions of currency/time), so they have dimensions of time. With currency units of US dollars (or any other currency) and time units of years (GDP per annum), this yields the ratio as having units of years, which can be interpreted as "the number of years to pay off debt, if all of GDP is devoted to debt repayment".