Bubble maps place proportionally sized circles on geographic regions to compare quantities across locations. They are ideal when you need to show both where something occurs and how much of it there is.
This sample visualizes Christianity around the world by combining a bubble series for the absolute number of Christians with a choropleth layer for the Christian population percentage. It uses ISO country codes for geo binding, a linear color scale for the choropleth fill, min/max bubble sizing, and HTML tooltips that display both the formatted count and the percentage for each country.
See the Bubble Map documentation for all configuration options.