Complex sentence: Almost 35,000 South Australians served in the First World War, accounting for 8.5% of the South Australian population at the time, or 37.7% of men between the ages of 18 and 44.
Split into simpler sentences: Almost 35,000 South Australians served in the First World War. This number amounted to 8.5% of the South Australian population at the time, or 37.7% of men between the ages of 18 and 44.