The situation described suggests a negative correlation between the number of cars available for sale and the number of animals adopted from a shelter during September. Specifically, as the availability of cars decreases, the number of animal adoptions increases. This could imply that people may be redirecting their spending or attention from purchasing a car to adopting pets during that time.
A statement that encapsulates this relationship might be: "In September, a decrease in cars available for sale is associated with an increase in animal adoptions, indicating a potential shift in consumer priorities or behavior."