Nearly all North Koreans now live in an area with cellular network coverage, a new report shows, following years of state efforts to promote mobile devices as a means to more tightly control the population.

Two decades since the introduction of mobile telecommunications in Pyongyang and Rason, mobile phone usage has become “ubiquitous” in the isolated country and forms the basis for its private economy, according to 38 North.

Using a combination of satellite imagery, state media footage and first-hand accounts, the website mapped over 1,000 cellular base stations across the country, while suggesting actual coverage will be greater