This graph shows light vehicle sales since 2006 from the BEA (blue) and an estimate for June 2020 (red).
The impact of COVID-19 is significant, and it appears April was the worst month.
The second graph shows light vehicle sales since the BEA started keeping data in 1967.
Sales collapsed in the second half of March, and really declined in April.
However sales rebounded in May, and increased further in June.