More than a fifth of forms are outstanding in West Dunbartonshire, where the return rate is 78.5%.
The figures, released by the National Records of Scotland, showed two council areas have now had forms completed by more than nine out of 10 households, with 91.1% returned in the Western Isles and 90.2% returned in Aberdeenshire.
Meanwhile, there are 19 council areas have reached 85% as the census enters its final full week.
Across Scotland so far a total of 2,210,265 households have completed the survey, with more than four in every five households having done so in 30 local authority areas.
Completed census questionnaires should be submitted by the end of May, with those who fail to do so potentially facing prosecution and a fine of up to £1,000.
“It’s great that we are seeing this increase in census response rates right across Scotland, but it is vital that we secure as high a rate as possible so that the census can be effective in delivering its many benefits for future public services.
“Census data informs how and where public money is spent on vital services, from the building of new schools and hospitals to improving transport links and understanding health needs.”
Mr Robertson said: ““I would urge everyone who has not completed their census to do so immediately and before the end of May, to avoid the risk of prosecution.
“Our field teams are out each day visiting those addresses across Scotland where we know we have not received a return and offering to fill in your census return there and then, supporting those who still need help.”
Liberal Democrat MSP Willie Rennie complained that the “census is being completed at a snail’s pace”.
He added: “We can’t afford for this once-in-a-decade opportunity to inform the delivery of public services to fall short.
“The Scottish Government needs to be open about why progress continues to be slow.”