Woburn-based Northern Bancorp. Inc. is one of the top 100 community banks in the country, according to SNL Financial, a Virginia-based data collecting firm.

SNL ranked banks between $500 million and $5 billion in assets based on profitability, asset quality and growth for the 12-month period ended Dec. 31, 2011.

Northern Bank & Trust Co.’s parent company, with $734 million in assets, was ranked No. 20 on the list, and is the only New England bank in the top 25.

The top bank on the list was Atlanta, Ga.-based State Bank Financial Corp., which won out despite being based in a state that has seen 77 failures since 2008, SNL said in a statement. State Bank acquired "12 of its fallen peers through failed-bank transactions over that time period, including two in 2011," SNL noted.

The metrics used by SNL were: return on average tangible assets before tax, net charge-offs as a percentage of average loans, adjusted "Texas ratio," efficiency ratio, net interest margin and loan growth. SNL measured each company’s standard deviation from the mean of each metric. The standard deviations, which are each equally weighted, were added together to calculate a performance score for each company.