Boston-based Safety Insurance Group Inc. has reported $12.8 million in net income for the first quarter, compared to $11.8 million for the same period last year.

Safety’s book value per share increased to $41.72 at March 31, from $41.20 at Dec. 31, 2009. Safety paid 40-cents per share in dividends to investors during both the quarters ended March 31, 2010 and 2009. Safety paid $1.60 per share in dividends to investors during the year ended Dec. 31, 2009.

The board of directors also declared a quarterly cash dividend of 40-cents per share on the issued and outstanding common stock.

The dividend will be paid June 15 to shareholders of record at the close of business on June 1.