As soon as the bonus disappears, the average bulk-billing rate for Australian children falls from 90 per cent, for under 16s, to 72 per cent for 16- to 18-year-olds. As soon as the bonus disappears, the average bulk-billing rate for Australian children falls from 90 per cent, for under 16s, to 72 per cent for 16- to 18-year-olds. Politics / Federal Sydney Morning Herald – Latest News