The Digital Migration working Group is not an individual. It was formed in 2013 by the Swiss radio industry and the Federal Office of Communications. It includes representatives from the multipex operators, the state broadcaster and all commercial and private radio stations.
Since 2015 Switzerland's leading market research company GfK has been asking people which platform they have used and for how long when listening to radio stations and reporting back to them. RAJAR also uses leading market research companies for their quarterly data. No bias involved when asking people which platforms they have used when listening to radio stations and for how long.
Digital Raio Insider is one individual in Sweden running a non profit organisation the Public Service Council, not clear how many members who need to pay a fee he has. He doesn't quote any statistics for FM listening in Switzerland, which is lower in Italian speaking cantons, just that it's "still extensive." In fact it's gone from 51% in 2015 to 13% in 2025 and the remaining listening is evenly split between online/internet and DAB+