[dennisw]

You sir are correct. In a year like 1979 200,000 Jap import cars came in and total Automobile sales were ~8-10 million. So Japanese cars were about 2-4% of the market

[Toddsterpatriot]

Google Books

According to the above source, in 1980, Japanese imports in 1980 were 21% of US sales. Total imports were 37% of US sales.