New figures from the Central Statistics Office show that the number of new cars licensed last year fell by 4.6% while the number of used or imported cars rose by 7.5% to the highest level ever recorded.
Today's CSO figures show that a total of 121,157 new private cars were licensed for the first time last year.
But the number of used or imported private cars licensed rose by 7.5% to 99,456 from 92,508 in 2017 - the highest annual number on record - due to the slump in the value of sterling which makes it more attractive to buy and import vehicles from the UK.
Overall a total of 220,613 new and used private cars were licensed in 2018 - the highest figure since 2007 when a total of 239,473 new and used cars were licensed.
The CSO said that all but three counties - Carlow, Kildare and Louth - showed a decrease in the number of new private cars licensed for all of last year.
It also revealed that 48.8% of all new private cars licensed in the country last year were licensed in Dublin and Cork.
Volkswagen was the most popular make of new private cars licensed in 2018, followed by Toyota, Hyundai, Ford and Nissan.
Together these five makes represent 46.2% of all new private cars licensed, the CSO said.
The CSO said that the most popular colour for new private cars licensed last year was grey (37.7%) followed by black (18.3%) and white (15.1%).
It noted that this was the same order in 2017 and the colour of choice for most new Volkswagen, Toyota, Hyundai, Ford and Nissan private cars licensed last year was grey.
Meanwhile, 54.3% of new private cars licensed were diesel in 2018 compared with 64.9% in 2017.
The CSO also said that 7.1% of new private cars licensed were electric/electric hybrid, a jump of 66% compared with 2017.
Looking at December alone, the CSO said that 778 new private cars were licensed for the first time, an increase of 29.5% compared with December last year.
And the number of used or imported private cars licensed increased by 1.6% to 6,461 compared with the same month in 2017.
The CSO also noted that January to June remained the most popular time for licensing new private cars (68.5%) in 2018, with almost half being licensed in the first quarter (48.2%).
The most popular month for licensing new private cars in 2018 was January (21.3%) followed by July (17.1%).
Licensing and registration of cars and other vehicles are different processes. A vehicle is licensed when a valid motor tax disc is issued for the first time whereas registration occurs when a vehicle gets its licence plate for the first time.