U.S. newspaper industry revenue continued to fall last year, as increases in circulation revenue failed to offset shrinking demand for print advertising.

The Newspaper Association of America says the industry's revenue fell 2.6 percent to $37.59 billion in 2013.

Revenue from print advertising dropped 8.6 percent to $17.3 billion, while revenue rose 3.7 percent to $10.87 billion.

Newspapers have looked in recent years to replace declining and circulation revenue with contributions from online sources.

While digital advertising revenue increased 1.5 percent to $3.42 billion last year, it is still less than 10 percent of the industry's overall revenue.

The NAA's numbers are based on a sample of public and private company data collected on a confidential basis.