An annual franchise tax on the exercise of the corporate franchise to engage in contacts with this state that produce gross income attributable to sources within this state is imposed upon every corporation that so exercises its franchise during the taxable year.
Contacts within this state do not include transportation in interstate or foreign commerce, or both, by means of ships navigating within or through waters that are made international for navigation purposes by any treaty or agreement to which the United States is a party.
The tax so imposed is measured by the corporations' taxable income and alternative minimum taxable income for the taxable year for which the tax is imposed, and computed in the manner and at the rates provided in this chapter.