
Explanation: On the x-axis of this diagram the number of confirmed Covid-19 infections is plotted with a logarithmic scale, on the y-axis the average daily increase of confirmed infections in percent (7-day average) is shown. For countries with more than 20.000 confirmed cases a circle (“bubble”) is shown for each of the 7 days from 20.04.2020 to 26.04.2020, where the area of the circle (at least for the larger circles) is approximately proportional to the number of confirmed Covid-19 infections.
So, the diagram shows the growth of the absolute number of cases for the last 7 days and the development of the key figure “average daily increase of confirmed cases in percent” at the same time.