N.H. Rev. Stat. Ann. § 282-A:79

The commissioner shall classify employers for each calendar year in accordance with their actual experience in the payment of contributions on their own behalf and with respect to benefits charged against their accounts, with a view to fixing such contribution rates as will reflect such experience, such rate to become effective with the fiscal year beginning July 1, 1951, and on each succeeding fiscal year beginning on July 1 thereafter.