The survey, conducted late last year among 1,000 households, found that only five per cent of households thought their income was higher than necessary, while 14 per cent thought they earned exactly as much as they needed.
This shows that nearly 80 per cent of households have problems in covering their costs, said GfK.
Its survey showed that the necessary income was 69 per cent higher than the earned income and that households cover the difference with credit and debit cards as well as overdrafts.
The survey found that all households had enough for food and utilities. Ninety per cent had regular costs for fixed and 84 per cent for mobile phones.
Eighty-eight per cent of households had regular costs for clothes and footwear, 82 per cent for traffic services, 77 per cent for medical services, 59 per cent for some form of entertainment, and 50 per cent for tobacco.
In 2005 about 50 per cent of households had costs for consumer durables, only 38 per cent had education-related costs, and only 22 per cent saved, either at home or in a bank.
Croatian households spend one-third of their income on food and beverages, and as long as their share does not drop under 20 per cent of a household's total costs it will be difficult to say that living standards have really improved, said GfK. When the costs of utilities and housing are added, it transpires that half a household's income is still necessary to cover the basic existential needs.
Revenue per household in 2005 was about 335 kuna higher than the year before.
(EUR1 = 7.3 kuna)