Looks like each big drop is tied with each major conflict Russia was involved in at its borders (Georgia in 2008, Ukraine/Crimea in 2014, and Ukraine/Donbas in 2021). Pretty steep. Interesting to note that recovery to previous levels only happened after the 2008 slump, never after.
SeeYouHenTee OP t1_j61cs7c wrote
Sources
https://carsalesbase.com/russia-car-sales-data/
https://www.marklines.com/en/statistics/flash_sales/automotive-sales-in-russia-by-month#:~:text=In%20all%20of%202022%2C%20687%2C370,down%2067.2%25%20to%2054%2C811%20units.
I used Numbers to make the graph