Idaho Code § 63-3502A

There shall be levied against every cooperative natural gas association in this state a tax of three and one-half percent (3 1/2%) of its annual gross earnings, after first reducing such gross earnings by its cost of natural gas. This tax shall be in lieu of all other taxes on the property of such association exempted pursuant to section 63-602JJ, Idaho Code, of the tax year next preceding the filing of the statement hereinafter provided for, and which shall be paid in the manner and at the time prescribed herein.