When it came to automotive magazines on this website, which publishers controlled the market with the largest print volumes?

After some research, the annual publishing data from NW Ayer and Sons (later Gale Research) proved useful. Based in Philadelphia, Ayer had been around since the 1860s. It provided distribution volumes submitted by newspapers, trade, and general interest magazine publishers.

These sources used net paid circulation data in their annual tally. It is six months of printed magazine volumes after deducting left-over, unsold, returned, sample, exchange or advertiser copies. Net paid circulation numbers are sourced from audited and unaudited publisher results and from Post Office data. Unaudited publisher submittals are prone to error or exaggeration. Some publishers used "plug" numbers or estimates when they did not have actual data. This is obvious when the same net paid circulation number is submitted over multiple years.

The data presented here were extracted from several such compendia including N.W. Ayer & Sons Directory of Newspapers and Periodicals, Gale Directory of Publications & Broadcast Media, and Oxbridge Communication's The Standard Periodical Directory. The numbers were then annualized and rank-ordered high-to-low on annualized circulation for each year.

Not all publishers submitted data for every year. Only those titles with non-zero print data are included. Further, the data are for magazines published monthly, bi-monthly, or quarterly.

Printed Titles by Decade