Department of Infrastructure, Transport, Regional Development and Communications
Financial year data.    Source: ACMA Communications report 2018-19, pp. 4.   "The collective 4G network coverage reached in   excess of 99.4 per cent of Australia’s population in 2019."    https://www.acma.gov.au/sites/default/files/2020-02/Communications%20report%202018-19.pdf  