This article tracks the progression of Covid-19 over the past six months on a state-by-state basis and provides a framework for interpreting these curves by including curves for seven other countries. While 52 states and territories are covered here, it turns out that there are just three basic stories told by the curves.

The world

In order to have a frame of reference for understanding the progression of Covid-19 within the United States we will begin with graphs showing the progression in some other countries. The values plotted for each country are the cumulative number of confirmed cases of Covid-19 per thousand population. These values were computed at the end of each calendar week. When these weekly per capita values are plotted for each of the 26 weeks between March 1 and August 29 we end up with the running records shown in figure 1. These curves allow us to compare levels between countries and also to see how these levels are changing over time. In this way we can see where the pandemic is growing rapidly and where it has been slowed down.

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