This visualization shows the number of Go tournaments in European countries over the years.
Circle sizes can either represent the relative number of tournaments for their respective countries only, or they can represent the relative size (on a quadratic scale) for all countries combined; use the radio buttons to switch between those two views. Mouse over the country names (or tap on them a mobile device) to show the absolute numbers. Change the checkboxes to show or hide tournament classes (classes are explained here).
The source data is provided by the European Go Database. I will update this visualization as new data appears there.