An interesting chart circa 1977 allows the following figures for

Region; population [in 1,000s] , chess players [in 1,000s], titled players
[masters and GMs]

USSR 250,900 4,180 84

Eastern Europe [7 countries
126,900 209 168

USA 212,900 50 39

Western Europe [15 countries
328,500 153 103

Source: Fide and Arpad Elo. Caveat [Elo's] not every country provides
reliable data.

In the same set of references* there is a figure for 1950 when the title
systems was first standardised by Fide, there were 27 grandmasters, and 94
masters. By 1977 there were 157 grandmasters and 355 masters.

Phil Innes

* Chapter, "The Sedentary Sport 1914-1980", title; Chess, The History of the
Game. Author Richard Eales.