Peak: 2999 BC (8.7%) Intensive agriculture came later to Mexico than the Old World, so Mexico has the highest numbers at the start of the data.

Peak: 1939 (8.8%) World War Two sharply reduced the size of the German economy. It recovered in its absolute terms, but growth in the rest of the world reduced its relative importance.

Peak: 1 CE (9.4%) Maddison’s data only goes back to 1 CE. At that point, Italy was relatively wealthy as result of tribute collected throught the Roman Empire.

Peak: 1870 (9.5%) The United Kingdom was the first country to industrialize. After 1870, the United States and Germany catch up.

Peak Year: 1945 (27.7%) The United States peak reflects that most other countries had been battered by WW2. The US proportion has fallen steadily since then as other countries recovered from the war and developed on their own.

Peak Year: 1100 BCE (33.7%) Nadir: 1974 (2.8%) Agriculture came to the Ganges plain early, but as the rest of the world caught up, India’s relative importance declined. The industrial revolution came late to British India and the main part of the population remained in subsistence agriculture until the 21st century. The socialist economics brought…

The figures in the Maddison and HYDE databases are usually in terms of the modern boundaries. There is some interesting in analysis to be done using those figures without reference to the historical boundaries. Peak Year GDP: 39.8% of the world GDP in 1100 CE (22.2% of population) Nadir: 3.7% of world GDP in 1961…

States emerged gradually from loose tribal entities. In most locations, this process is poorly documented as the invention of writing tends to occur at around the same time as states. In general, I am giving proto-states the benefit of the doubt, as I think it more useful to include something instead of “None”. For example,…

Sometimes the iconography of a state continues but the state itself does not actually control its territory or a significant part of its territory. This is often in the context of a civil war, but not always. Somalia, Congo and Haiti are current examples of failed states. Historically the Holy Roman Empire and the interregnum…

Civil wars are common throughout history. They may be efforts an area to secede from existing state (American Revolution, American Civil War), to take control of an existing state (English Civil War, Chinese Civil War) or both (Russian Civil War). Most geographical sources neglect these events. Geacron does not show the United State until 1784.…