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The economic history of the United States spans the colonial era through the 21st century. The initial settlements depended on agriculture and hunting/trapping, later adding international trade, manufacturing, and finally, services, to the point where agriculture represented less than 2% of GDP.
The chronology of the universe describes the history and future of the universe according to Big Bang cosmology.. Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level.