U.S. auto industry ad spend for the first seven months of this year fell 4% year-on-year as inventory shortages crimped sales even as vehicle demand stayed strong, according to data from an advertising research firm.

Digital ad spending accounted for 53% of the totall $4.80 billion the industry spent during the period, according to data from Standard Media Index (SMI).

The overall ad spend was 12.7% less compared to the same period in pre-pandemic 2019 at $5.50 billion, as spending from dealerships, traditionally among the biggest in the industry, suffers due to a shortage of vehicles.