(a) A tax is imposed upon every generation-skipping transfer in an amount equal to the amount allowable as a credit for state legacy taxes under 26 U.S.C. § 2604.
(b) If any of the property transferred is real property in another state or personal property having taxable situs in another state which requires the payment of a tax for which credit is received against the federal generation-skipping transfer tax, any tax due pursuant to subsection (a) of this section shall be reduced by an amount which bears the same ratio to the total state tax credit allowable for federal generation-skipping transfer tax purposes as the value of the property taxable in the other state bears to the value of the gross generation-skipping transfer for federal generation-skipping transfer tax purposes.