In the January-May period Croatians registered 21,241 new personal cars, which was by 18,638 cars less than in the comparable period of 2008.
The agency reported that new passenger car registrations fell in the first four months of 2009 throughout Europe according to statistics provided by the European Automobile Manufacturers' Association.
In Croatia, Opels were the best selling cars in the first five months with 2,263 sold vehicles, accounting for 10.7 percent of the market.
Opel was followed by Volkswagen with 2,002 sold cars or 9.4 percent of the market.
Renault came third with 1,925 cars or a 9.1-percent share in the market.
Also among popular cars were Peugeot, Skoda, Ford, Citroen, Suzuki, Toyota and Chevrolet.
Although they were not in this group, Lancia, Dacia, Smart and Nissan saw a rise in their cars' registrations in Croatia in the first five months of 2009 compared to the same period in 2008.
In the first five months the market of used passenger cars shrank by 23.8 percent to 3,895 registrations.