The Historical Rise of the US Economy

Greg Mankiw posted this graph today from Angus Maddison's historical analysis of world GDP. Although there are plenty of criticisms of the data, it is nonetheless an impressive graph.
The size and scope of the US economy is awe inspiring. At our peak, we accounted for about 25% of the world's GDP.

The reasons for our success? According to Michael Milken in the Wall Street Journal:

Our remarkable growth since 1820 has benefited from democratic institutions, a belief in capitalism, private property rights, an entrepreneurial culture, abundant resources, openness to foreign investment, the best universities, immigration and relatively transparent markets.

I'd have to agree.