GDP is the single most commonly referenced figure to cover the entirety of a national economy and its trajectory in a single statistic. Measured on the basis of purchasing power parities (PPP), GDP can be used for comparisons among peer countries.
Using purchasing power parity with GDP involves a decrease of bias in economy estimation as PPP takes into account the relative cost of local goods, services and inflation rates of the country.
Looking at the GDP figures from historic perspective allows understanding on what phase is the economy of a country at the moment. The data on GDP from the World Bank covers the period for the last half of the century.
Take a look at other GDP-related dashboards: