Sources describe most Pama-Nyungan languages as spoken by small ethnic groups of a few hundred speakers or fewer, with almost all remaining ones endangered, but no tertiary source consulted sums these many small communities into a single family-wide total.
What would resolve this An Australian government or AIATSIS-level survey aggregating speaker counts across every living Pama-Nyungan language at one point in time.
OpenAustralian Aboriginal linguisticsWikipedia: Pama-Nyungan Languages