Average health savings account balances climbed to $1,400 in January, from $1,028 in December 2006.

The number of HSA accounts grew 73% over that period, to 2.1 million, and the HSA asset total increased to $2.9 billion, according to researchers in the San Francisco office of Celent L.L.C.

Average revenue per account ranged from $12 to $120 during the period studied, while the cost of administering the accounts ranged from $22 to $110 per account, the Celent researchers report.