Drill a 1-1/2-inch entrance hole in the front piece with a spade bit for eastern and western bluebirds. In areas where mountain bluebirds reside, drill the entrance hole 1-9/16 inches. Center the hole about 1-1/2 inches from the top of the board. Starting about 1/2 inch below the entrance hole, make three shallow cuts about 1/4 inch apart on both sides of the front board. On a table saw, set the blade at 1/8 inch deep and use the saw's miter gauge to cut the notches.
The data-point at issue in both cases is gross domestic product, or GDP, the total value of all goods and services produced within an economy each year. GDP is of critical economic importance; thousands of economists use estimates of the total amount spent or (equivalently) earned each year in their research. Governments also rely heavily on the figure, to shape policy or determine how much public spending is affordable. Yet GDP seems an impossibly complex thing to measure in a modern economy.
GDP and GNP figures are both calculated on a per capita basis to give a portrait of a country's economic development. GDP (or Gross Domestic Product) may be compared directly with GNP (or Gross National Product), to see the relationship between a country's export business and local economy. A region's GDP is one of the ways of measuring the size of its local economy whereas the GNP measures the overall economic strength of a country.