The cost of motor insurance claims rose just 3% between 2013 and 2016, despite premiums rising 70% in that time.
The PIAB figures cast doubt over the insurance industry's assertions that higher claim costs were increasing premium prices.
However, the average price of a premium has dropped by 10% in the past year, according to CSO figures.
Social Protection Minister Regina Doherty says people are understandably frustrated but says new government measures will make a difference in premium prices.
"Any of the changes by Eoghan Murphy over the last couple of month are going to take 12-18 months to filter in.
"There was a realisation that the changes to be made, there were 72 recommendations in that report, some of them are going to take longer to feed into a reduction in premiums."
