The Cox Automotive/Moody’s Analytics Vehicle Affordability Index increased from 35.1 in March to 35.2 in April after five months of incremental improvement, signaling higher acquisition costs for U.S.-sold new vehicles.

Based on the number of weeks the average American would have to work to pay for the average purchase, the index is susceptible to market factors beyond dealers’ control, including prices, interest rates and incentive spending.

Analysts note affordability did improve on a year-over-year basis as higher prices were offset by lower rates and higher incentives.

“The result: While monthly payments in April were higher year over year by 1%, the estimated number of weeks of median income needed to purchase the average new vehicle was lower by 2.8%,” the report states.

Read the full report at Cox Automotive