Over two thirds of all Australians eligible to vote have now posted in their same-sex marriage survey forms, with three weeks still to run in the national vote.
The 10.8 million returned ballots amounts to 67.5% of the eligible Australian population.
By way of comparison, the Irish referendum on marriage in 2015 yielded a 60.5% turnout, while the 2016 US presidential election had a turnout of around 55%. Unlike Australia, neither Ireland nor the US has regular compulsory voting.
The rate of return in the past fortnight has remained steady, with about 5%, or 800,000 people, returning their survey in each of those weeks.
A spokesperson for the Australian Bureau of Statistics (ABS) told BuzzFeed News that 120,000 replacements forms had been issued over the course of the survey.
Anyone who has not received their ballot, or damaged their form in some way, can request a replacement from the ABS up to 6pm on Friday October 20.
"This is the third weekly estimate of the number of survey forms received and comes as time is running out for eligible Australians to order a replacement survey," the ABS said on Tuesday. "This is your last chance."