New Jersey Statutes Title 54. Taxation 54 § 35-3

If such tax is not paid within 8 months after the date on which it became due and payable pursuant to R.S. 54:35-1, the tax shall bear interest at the rate of 10% per annum from the expiration of 8 months after the date on which it became due and payable to the date when the tax is paid, unless, payment was tendered by the taxpayer within the 8 months period and is evidenced by the postmark on the letter conveying the payment, or by other acceptable proof, but was not credited through no fault of the taxpayer, in which case no interest shall be charged, or unless, by reason of claims made upon the estate, necessary litigation or other unavoidable cause of delay, the decedent's estate, or a part thereof, cannot be settled before the expiration of 8 months from the date on which said tax became due and payable, in which case only 6% per annum shall be charged from the expiration of such 8 months until the cause of delay is removed; provided, however, that if the decedent shall have heretofore died or shall hereafter die while a member of the Armed Forces of the United States, no such tax shall commence to bear such interest until the expiration of 8 months after receipt of official notification of the death of the decedent by the wife, husband, father, mother, or next of kin of such decedent.