Car sales are seen as a useful measure of the economy's wellbeing.
New car sales in Northern Ireland fell by 5% in September compared to the same month in 2016, according to industry figures.
Car sales are seen as a useful measure of the consumer economy in Northern Ireland as there are no general retail sales figures. In the UK as a whole, sales of new cars fell sharply in September.
The figure was down 9.3% from September last year, while diesel sales - which have been hit by worries over air quality - fell by 21.7%. It is the first time in six years that the key September market has fallen.
