Scotland's population is growing more diverse and self-reliant, with a steep rise in people living alone and a doubling in the number of non-white residents, the latest census figures show.

Statistics from the 2011 census reveal a decline in the number of people identifying themselves ethnically as white Scots in the past 10 years, down by 13,000 people. But there has been an increase in Poles, south Asians and black residents.

Rates of single occupancy homes have soared, from 14% in 1961 to nearly 35% in 2011, and the number of single people has risen by five points to more than 35%. In 1991, only 16% of households had two or more cars; that had risen to over 27% in 2011.

With Scotland's minority ethnic population now standing at 4%, double the number of 2001, the census also finds that 15% of those people born outside the UK are Polish (55,000 people overall), and 9% of Scotland's 5.3 million residents were born in England."

The figures show that Glasgow, Edinburgh and Aberdeen are the most ethnically diverse places in Scotland, with 12% of Glaswegians citing themselves as either Asian (8%), African (2%), Caribbean or black, or belonging to another ethnic group.

Glasgow also had the lowest number of married residents, at just over 30%, against a Scottish average of 45%, down five points since 2001. The city has lowest number of car owners, at 49%.

Orkney and the Western Isles appear the least diverse, with more than 99% of their populations describing themselves as white. Overall, the number defining themselves as "white Scottish" has fallen from 88% in 2001 to 84% in 2011, with white British and "other white" numbers up from 9.9% to more than 12%.

Edinburgh and Aberdeen's non-white populations were just over 8%, double the Scottish average. Adults in the two cities, which are by far Scotland's most prosperous and economically significant, also recorded the lowest levels of self-identification as Scottish.

While the overall proportion of adults nationally describing themselves as Scots stands at 62%, and 18% are calling themselves Scottish and British, in Edinburgh less than half of adults (49%) and 55% of adults in Aberdeen say they are "only Scottish". A majority of Edinburgh's residents say they have dual Scottish-British, British, English or other identities.

In Edinburgh, the UK's second largest financial centre, as well as Aberdeen, home to the largest oil and gas industry in Europe and a large Polish population, and Glasgow, Scotland's most diverse city, the number of people born outside the UK has also mushroomed since 2001.

Ten years ago, just over 6% of Aberdonians were born abroad; that figure now stands at 16%. In Edinburgh, the proportion has doubled to 16% in 10 years, and doubled too in Glasgow, to over 12%.

One person in six in Aberdeen city was born abroad, while in East Ayrshire, that figure was one in 44. More than 70% of residents in West Dunbartonshire and North Lanarkshire identified themselves as solely Scottish.

The census report, the latest in a series of papers looking in detail at the 2011 figures, also shows a steep slump in the numbers of people describing themselves as members of the Church of Scotland, the country's largest and once most influential church.

Overall, in answers on religious identity (the only voluntary question in this census), 54% of residents said they were Christian, down 11% since 2001. Meanwhile, those describing themselves as having no religion jumped by 9% to 1.9 million.

The census finds that while 1.7 million Scots said they belonged to the Church of Scotland, that number has fallen 10% since 2001, while the proportion of Roman Catholics has stayed the same, at 16%. That is likely to be largely due to Polish migration.

It also reveals that the influence of Star Wars on modern culture is diminishing. In 2001, more than 14,000 people identified their religion as Jedi Knight; in 2011, it stood at 11,700.

The census also suggests that recent efforts by successive Scottish governments to invest in Gaelic schools may be saving the language from decline.

The overall number of Gaelic speakers, heavily concentrated in the Western Isles, has fallen by 1,000 since 2001 to 58,000 (1.1% of the overall population). But the number of children of all ages speaking the language has grown. In total, 87,000 people reported being able to read, write or understand Gaelic, down 5,000 from 10 years ago.

Scottish government ministers were also pleased that the number of residents saying they could speak or understand Scots – regarded by the government as a distinct language – stood at 1.5 million. That language was included in 2011 for the first time in the census.

• This article was amended on 27 September 2013. It used a statement in the Scotland census bulletin (pdf) that said the number of people identifying themselves ethnically as white Scottish in 2011 was 4.4 million, down from 4.5 million in 2001. From this it was taken that there had been a drop of 100,000 people. However, a table further on in the bulletin shows that these were figures were rounded down (from 4,446,000) and up (from 4,459,000) respectively, and the actual drop was only 13,000. This has been corrected.