SimilarWeb is a platform for web analytics. It allows you to collect data for any sites even when you are not their owner. It is an expensive tool but some features are available for free for the start period. When I tested how it worked naturally I chose 'Codeforces.com' for my exercises:-)

The very first picture surprised me.
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I remembered for sure that the top 5 countries with the great amount of users are
India 34063
China 15750
Russia 10343
Bangladesh 8453
Egypt 3729

I counted these values by code but you can see them on RATING page.

There is a table with more details as well, in free version only the first 10 rows are available:

I should admit it is my favorite diagram. I really enjoy data in the Country rank column. Isn't it cool that Codeforces.com is a so popular site in Georgia and Bangladesh?

Using Codeforces API I counted the number of users who participated in rated contests during the last month. Top 15 are

India 8622
Bangladesh 1415
China 1377
Russia 617
Vietnam 341
Egypt 339
Japan 234
United States 211
Ukraine 210
South Korea 169
Syria 159
Taiwan 141
Iran 130
Kazakhstan 129
Brazil 108

Number of active users is more correlated with traffic data. But some diagrams are still difficult to explain.

I do not have any reasonable idea how to find 33% of females between codeforces.com visitors:-) And it is a pity that there are no data about the youngest group. There are obviously pretty much participants under 18, but it would be interesting to know if there are some codeforces users from kindergarten.

And a couple more of diagrams: