For most countries, data on GDP were not available before 1914, and therefore, proxy variables, such as Gross National Product (GNP) or Net National Product (NNP), were used for computing debt ratios in the earlier years. From 1914 through 1980, GDP data for most countries were mainly sourced from Mitchell (2003). 7 Government publications were also used for collecting GDP data for some countries, including Canada, Italy, Japan, the Netherlands, New Zealand, the United Kingdom, and the United States. For some Latin American countries, GDP data were taken from the Oxford Latin American Economic History database, which covers 1900–2000. GDP data.
