N.J. Stat. § 54:4-2.27
Each county board of taxation shall, by resolution, establish the percentage level of taxable value of real property on or before June 1, 1964 as to the tax year 1965 and thereafter on or before April 1 of the year preceding the tax year, and the level so established shall be applied uniformly in such county for the purpose of assessing the taxable values to be used in levying taxes for the calendar year next succeeding the year in which such level was established. The level so established may be altered by any such board by establishing, on or before the date fixed by this section in any year, a new level; but the percentage level last established pursuant to this act shall remain in full force and effect for a period of not less than 3 years and until altered as provided in this section. In the event that the county board of taxation for any county shall fail to initially establish the percentage level for such county, then until the same shall be done the level of assessment shall be 50% of the true value. The secretary of the county board of taxation, not later than June 10, 1964 and April 10 of each year, shall mail to the Director of the Division of Taxation, to each assessor and board of assessors, and to the municipal clerk of each municipality within the county, a copy of such resolution, or, if such resolution was not adopted, a statement to that effect.
N.J.S. § 54:4-2.27