TROY, Mich.–(BUSINESS WIRE)–J.D. Power: The Retail Sales Forecast New-vehicle retail sales for December 2021 are expected to decline when compared with December 2020, according to a joint forecast from J.D. Power and LMC Automotive. Retail sales of new vehicles this month are expected to reach 1,105,800 units, a 17.4% decrease compared with December 2020 when adjusted for selling days. December 2021 has one fewer selling day than December 2020. Comparing the same sales volume without adjustin