The official verdict of businesses on their recent performance show that Northern Ireland suffered a "sharp recession" in 2009, an economist said.
Northern Ireland's latest annual business inquiry reveals that overall net input fell 4.6% to £16.9bn last year, a fall of £821m on 2008.
UK-wide, overall net input -also known as GVA (gross Value Added) and a measure of the income generated by businesses after costs are taken out -fell by almost 6%.
The inquiry by the Department of Enterprise, Trade and Investment showed that in Northern Ireland, GVA in production industries fell by 6.5%, construction by 14% while spending in shops, described as wholesale and retail, was down 5%.
But in most categories Northern Ireland business trends were less severe than elsewhere in the UK - though the collapse in wholesale and retail was steeper than the UK as a whole, where it dropped by 4.6%.
The inquiry collects employment and financial data from businesses which account for around two-thirds of the economy. But the inquiry only gives information in arrears after firms are able to give solid performance data on on how they have been affected.
Economist John Simpson said: "The official statistics now confirm that Northern Ireland output and incomes were being dramatically affected in 2009 compared to 2008."
While the fall in GVA in 2009 was 4.6%, Mr Simpson said that in real terms it could be as much as 6.5%.
"By the standards of any recent previous year, this was a sharp recession. There is one slight reassurance. Compared to the overall UK experience, this was a smaller reduction than the national average of 5.9% in current prices."
Private sector employment in 2009 was 46,000 lower than the 563,000 of 2008. Employment was down 8.1% with 8,000 fewer jobs in manufacturing, 10,000 fewer in construction, 14,000 lost in retail and whole and 14,000 lost in the remaining service sectors.
Mr Simpson said the trends of 2009 were likely to have continued into this year. "Early evidence is that manufacturing and retailing will have had slightly better results in 2010 but the rest of the services sector as well as the construction industry are now thought to be suffering more sharply than elsewhere in the UK."