not very accurate since gulag system fired up right away when cheka took over and it was later continued by both nkvd, kgb and those lesser known in between > the solovki prison camp, the first correctional labour camp which was constructed after the revolution, was opened in 1918 and legalized by a decree, "on the creation of the forced-labor camps", on april 15, 1919. > the internment system grew rapidly, reaching a population of 100,000 in the 1920s. by the end of 1940, the population of the gulag camps amounted to 1.5 million.[12]    yes the nkvd period was the most brutal one but really those were the same organisations over and over again and they had the actuall power in soviet union and later russia
Poland