Complex sentence: By 1900 the recorded Indigenous population of Australia had declined to approximately 93,000 although this was only a partial count as both mainstream and tribal Aboriginal people and Torres Strait Islanders were poorly covered with desert Aboriginal peoples not counted at all until the 1930s.
Split into simpler sentences: By 1900 the recorded Indigenous population of Australia had declined to approximately 93,000. However, this was only a partial count as both mainstream and tribal Aboriginal people and Torres Strait Islanders were poorly covered, with desert Aboriginal peoples not counted at all until the 1930s.