Study the given table and answer the question that follows.

The table shows the production of five types of cars by a company for the years 2018 to 2021.

Year →	2018	2019	2020	2021	Total
Car ↓
A1	10	20	19	6	55
A2	14	15	16	14	59
A3	21	16	13	14	64
A4	7	10	9	25	51
A5	20	16	19	16	71
Total	72	77	76	75	300

In which year was the production of cars of all types taken together equal to the average of total production during the period?