The decline was one per cent in nominal and 4.4% in real terms.
Five macroeconomists polled by Hina predicted that the year-on-year decline would be 3.9 per cent on average.
The year-on-year decline in retail trade in April was 7.3% and was the biggest since April 2010.
Retail trade grew a little in the first two months of 2012 but dropped significantly in the following three.
Zdeslav Santic, chief economist at Splitska Banka, said the decline was due to lower household incomes, low employment and a modest growth in net wages as well as to higher energy and utility prices.
He predicts that annually, retail trade will fall about three per cent.
Santic said the summer tourist season could improve consumption, but not significantly because many European countries were in crisis.
The steep drop in industrial output and consumption in April and May indicates that the economic downturn in the second quarter of the year will be bigger than in the first, when gross domestic product fell 1.3%.