The proportion of families who are unable to save anything on a monthly basis has also risen, from 40pc in January last year to 42pc.
Louise Colley, head of protection sales and marketing at Aviva said: “While average incomes have increased over the past year, the prices of essential goods and services have also increased, meaning families are struggling to keep up.
“Many appear to have acclimatised to this economic environment by shopping around and seeking to minimise their spending in certain areas.
“However, at the same time there are still a worrying number of families with insufficient savings or large debts.”
Couples without children have seen the biggest income rises generally, while single parents have seen their incomes plummet.
Couples who are planning to have children reported an 11pc year-on-year increase in monthly income to £2,433, while those living with a partner who do not plan to have children had a 10pc annual rise to £2,220. Both these groups tend to derive their income from a full-time “breadwinner” wage.
In sharp contrast, parents who had been divorced, separated or widowed have been particularly badly hit, seeing their typical incomes tumble by a fifth over the year to £1,075 a month, Aviva said.
The report said: “This decrease has possibly been exacerbated by the changes to benefit payments which came into force in 2011, and also the impact of rising unemployment over the year.”
The percentage of family cash spent on food has remained constant at around 10pc, despite price hikes, suggesting people are shopping around more, the report said.
But the report said there has been a “notable drop” in the amount spent on children’s activities from 4pc of monthly income in January 2011 to 1pc this month.
The report took its findings from more than 10,000 people across the UK.