GDP stands for “gross domestic product” and is a measure of value creation. It is the sum of everything a country produces in terms of goods and services in a year.
The GDP shows the value of everything produced in a country during a certain period, usually a calendar year, and includes the value creation in all business activities, public administration, and non-profit organisations. To find the BNP you have to sum up all goods and services produced in a country in a year and subtract the goods and services used in the production.
GDP is a common indicator of the economic condition of a nation and is also used as one of the indicators (but not the only one) of the overall well-being of the population.
A country can look at their GDP for each year and then compare the economic state.