April sales were hit by a non-working period ordered by Russian President Vladimir Putin to stop the spread of the coronavirus, bringing the economy to a halt after factories and businesses were forced to suspend operations and citizens asked to self-isolate.
The AEB said it does not expect much better sales results in May.
People rushed to buy cars in March, with sales jumping 23 percent as they expected prices to rise after a fall in the ruble due to lower oil prices and the coronavirus outbreak, analytical agency Autostat said last month.
Russia has reported 232,243 coronavirus cases and 2,116 deaths.
All key brands fell in April with the market's best-selling marque, AvtoVAZ, dropping 71 percent. Kia, in second place, was down 78 percent, with No. 3 Renault falling 75 percent.
In fourth place, Volkswagen brand fell 68 percent, while Skoda rounded out the top five with a decrease of 59 percent.
Click here for Russia sales by brand in April
Through April, Russia sales were down 19 percent to 415,102.