Black Book revealed that its Used Vehicle Retention Index for May fell 0.7 percent from April.

Currently, the retention index is at 112.3, down from 113.1 in April. In a 12-month analysis, the index has dropped 5.6 percent from May 2016.

The index declined as cars and trucks saw increased depreciation in May following a strong spring season during April. The index increased slightly from 113.0 in March to 113.1 in April. It was the first time the Index saw an increase dating back to Jan. 2015.

From April to May, sub-compact cars fell 1.6 percent, full-size cars dropped 0.7 percent, mid-size cars fell 0.6 percent, and sporty cars fell 1.0 percent. Premium sporty cars, on the other hand, saw a 0.4 percent increase.

In the trucks market, small pickups increased 0.5 percent from April, while full-size luxury utilities increased 0.1 percent, and full-size pickups held steady.

“There is not a lot of surprise in the May numbers, particularly after seeing arguably the strongest spring-season lift on record over the last three years in April,” said Anil Goyal, senior vice president of Automotive Valuation and Analytics for Black Book. “It is expected that we will see more declines in the Index in the months ahead as we move deeper into the year, particularly driven by softness among car segments.”