US newspapers suffered further revenue declines in 2013, seeing only mixed success in a transition to digital, according to industry figures.

Total newspaper industry revenue amounted to $37.59 billion in 2013, a 2.6 percent drop from $38.60 billion in 2012, according to a report released Friday by the Newspaper Association of America.

In one positive sign, the data showed a 3.7 percent increase in circulation revenues to $10.87 billion, helped by digital subscriptions and “paywalls.”

The figures showed revenue from all digital sources including advertising, circulation and marketing, rose 5.8 percent and accounted for 12 percent of total industry revenue.

But newspapers continued to see declines in print advertising, which has long been their most important revenue source.