As Fairfax prepares to shrink the size of its broadsheets and introduce a paywall next March, and News Limited struggles with its paywall approach, the latest circulation figures and quarterly reports from the US print media contain deeper warnings about the difficulties of such a switch, despite solid digital gains for papers like The New York Times and The Wall Street Journal.

The US Audit Bureau of Circulations survey for the six months to September shows that compared to the same six-month period in 2011, print and digital circulation fell 0.2% for the 613 Monday to Friday newspapers included in the survey, while sales for the 528 Sunday newspapers in the survey rose 0.6%. Digital circulations accounted for 15.3% of total circulation — a rise of more than 60% in 12 months, thanks to more papers like The NY Times going to variations on a paywall that has been in place at The Wall Street Journal for a number of years.

By total circulations, The Journal remained No. 1 with 2.3 million print and digital circulation, followed by USA Today (1.7 million) and The NY Times (1.6 million). On a print-only basis, USA was the biggest, followed byThe Journal and The Times.

So great was the impact on the NYT that its digital circulation now outweighs print sales. Total circulation jumped 40%  to more than 1.61 million a day, led by a 136% jump in digital subs on the past year to more than 896,000.

There was a 27.7% jump in the total circulation of the Sunday edition to 2.1 million. For the Monday to Friday paper, print sales fell 6.9% to just over 717,500 which left it third in the US behind the Wall Street Journal and USA Today. The Sunday paper saw a slower 1.8% drop in  print sales to just over 1.25 million, still the biggest selling Sunday paper in the US. It had more than 717,000 digital subs.

As impressive as that rise in digital circulation to more than 896,000, only part of that was paid. The Times said in last week’s quarterly earnings statement that only 566,000 subscribers are paying. That difference is part of the reason why it is hard for papers to monetise their growing digital subscriptions.

The Wall Street Journal, with its longer history of digital subscriptions, grew its total circulation by 9.4% in the September period to a total of 2.3 million as its digital circ surged by close to 50% to 794,594 from 537,469 a year ago. the 257,000 plus rise in digital subs at the Journal more than made up for a 60,000 drop in print sales in the latest period.

USA Today (published by Gannett) was the second biggest circulating paper at 1.7 million, down 3.9%. USA Today remained the leading print newspaper, with a higher circulation than the Journal after digital editions are excluded. But unlike the Journal and the Times, USA Today doesn’t charge for website access. Its digital circulation is limited to other products, such as subscriptions on Kindles.

According to the ABC report other US papers saw solid gains thanks to their evolving digital subscription strategies with 16 of the top 25 papers boosting circulations in the year to September. The Los Angeles Times (up 11.9%, and proving that being in bankruptcy hasn’t hurt the paper’s ability to adjust to the digital future. No wonder News Corp is sniffing around the paper and looking to swoop). The Denver Post (up 16.9%), Newark Star-Ledger (48.1%), and St. Petersburg Times (30.4%) all reported big gains as digital subs surged from a low base.