The States Statistics Unit today released the findings of the £165,000 household expenditure survey, which took two years to compile.
It shows that households in the four northern parishes spend over £880 a week, whereas households in St Helier spend about £510 a week.
Over 1,000 households took part in the survey, with about 2,000 people filling in diaries.
They recorded every purchase made in a two-week period.
They also recorded major purchases from September 2004 to September 2005.
In all, over 300,000 individual transactions were analysed.