Used-vehicle depreciation slipped to 1.5 percent in July, as mid-size sedans led a sharper decline in value after a strong spring, reports Black Book.

Each of Black Book's 24 vehicle segments fell in value in July. Full-size passenger vans showed the strongest retention rate by losing 0.3 percent with an average price of $15,955. Compact pickups including the Nissan Frontier, Ford Ranger, and Toyota Tacoma lost 0.5 percent of their value.

Upper mid-size sedans took the brunt of the depreciation slide, falling 3 percent with an average sales price of $12,005. This segment includes the Buick LaCrosse, Honda Accord, Nissan Altima, Toyota Camry, Volkswagen Passat, and Ford Taurus.

Full-size SUVs let all truck segments with the highest depreciation at 2.1 percent with an average price of $24,410. This segment includes the Dodge Durango, Ford Expedition, Chevrolet Suburban, and GMC Yukon.

The reports included vehicles from the 2009 to 2013 model years. Black Book projects overall 2014 depreciation to come in at 13.5 percent.