Households in Singapore across all major ethnic groups have brought in higher incomes over the past 10 years amid a growing trend of married, dual-career couples.

More Singapore residents are also living in condominiums and apartments now, and households with fewer members are becoming more common.

These were among key findings in the second of a two-part census report released by the Department of Statistics yesterday.

The census is an official count of the resident population - encompassing citizens and permanent residents - conducted every decade.

A total of 150,000 households were surveyed in the latest edition, which also collected, for the first time, data on geographic distribution of workplaces and difficulty in performing basic activities.

Overall median household income from work had risen 3.3 per cent per annum from $5,600 in 2010 to $7,744 last year - or 1.9 per cent in real terms, factoring in inflation. After accounting for household size, median household income from work per household member increased by 4.2 per cent per annum from $1,638 to $2,463 - or 2.8 per cent in real terms.

These jumps were reflected in the rising proportion of households in higher-income brackets.

Those earning at least $9,000 a month grew from 29.7 per cent in 2010 to 44.2 per cent last year.

Significantly, the share of households earning at least $20,000 more than doubled from 6.6 per cent to 13.9 per cent. This group also formed the largest proportion of households last year.

In contrast, the largest proportion in 2010 - 16.2 per cent - was for those earning between $3,000 and $4,999. This figure dropped to 10.6 per cent last year.

The overall proportion of those earning less than $9,000 stood at 42.5 per cent last year - a fall from 59.8 per cent in 2010.

At a media briefing, Minister in the Prime Minister's Office Indranee Rajah was asked about these income disparities and the implications for inequality. She said this was no different from trends being observed across the world.

"What we are doing in terms of working to create opportunities, economic growth, identifying new areas - that has obviously had some payoff," said Ms Indranee, who also oversees population issues.

"But at the same time, there will be groups who don't do so well. And you will remember that after the 2015 election... We had identified inequality as one of the areas that we need to work on.

"This is something that after the more recent election, we have said that we will continue to do.

"And you will see that a lot of emphasis has been put in terms of upskilling, job creation, job matching, and on the educational piece as well - all in an effort to help lift all boats and to raise incomes."

Over the decade, median household income from work also rose across the board for all ethnic groups. In nominal terms, last year's figures were $7,972 for Chinese, $5,704 for Malays and $8,500 for Indians.

After accounting for household size, it was Malay households that registered the highest growth per member (4.3 per cent per annum, or 3 per cent in real terms). Their median household income from work per household member was $1,594 last year, compared with $2,603 for the Chinese and $2,521 for Indians.

When asked how this gap could be addressed, Ms Indranee said it would require a combination of initiatives, with some already in place.

She pointed to the M3 collaboration between self-help group Mendaki, the Islamic Religious Council of Singapore and the People's Association Malay Activity Executive Committees Council; Social Service Offices in Housing Board precincts; the ComLink programme to support low-income households; and the Uplift task force helping students from disadvantaged families.

"It is an ongoing work," said Ms Indranee. "You will never get to a stage where everybody's equal, but what we want to do is try and make sure that the gaps are not too large and that different groups can be as close as possible."

The latest census identified that across all ages, the share of non-employed married couples have decreased over the decade, while the proportion with employed wives grew from 52.9 to 60 per cent. Couples where husband and wife were employed made up more than half of all married couples last year.

While the bulk of residents - nearly four in five - continued to reside in HDB flats, the proportion living in condominiums and other apartments grew from 11.5 per cent in 2010 to 16 per cent last year.

The share of single-person households also increased, alongside a decline in couple-based households with children from 56 per cent to 47.7 per cent.

For the first time, it was revealed that nearly 98,000, or 2.5 per cent of residents aged five and above, could not carry out or struggled with at least one basic activity, which includes seeing, hearing, mobility, remembering and concentrating, self-care or communicating.

The census also found that Singapore's city centre continues to draw the largest share of workers, and that Bedok was the most populated planning area of residence last year. Outram had the highest proportion of senior residents, while Punggol had the highest for those aged below five.