However far we can trust ICO rating sites (and the one I’m about to point out seems pretty dead), I’ve found one that kept a stat on the country of origin of each ICO they rated: https://icowatchlist.com/statistics/geo.

Estonia figures in 6th position, with around 4,09% of projects, but has the following countries with a greater share: United Stated (15,94%), United Kingdom (9,5%), Singapore (8,33%), Russian Federation (7,02%) and Switzerland (6,58%).
I’m not sure how trustworthy these figures are, but they could be considered a rough indicator. Looking over https://icobench.com/stats, Estonia figures in fifth place in the top countries by number of ICOs rating.