And it's important to know the definition of "GA" and "accident" and "incident" in the different countries over the period covered by the statistics.
Given the USA's topography and meteorological conditions compared with Australia, and given that a PPL in the USA includes night VFR authorisation with nowhere near the training required for a night VFR rating in Australia, one wonders why the rate of "GA" "accidents" and "incidents" is not much higher in the USA compared with Australia.