Mark the European countries you've been to and the counter shows how many you've visited out of the 57 on this map, and what percentage that is. It includes the microstates, and the Caucasus and Türkiye for anyone who counts them.
Switch to the world travel map, US states, another continent, or the regions of a single country from the Map menu.
Is it free? Yes. There's no signup and no account: your map is saved in its link, so keep the link.
How do I count the countries I've been to? Mark them on the map. The counter at the bottom and the chart in the corner show how many you've visited out of the total, and the percentage.
Can I show where I've lived, or where I want to go? Put those places in their own step, with a different color and label.