If an amount representing compensatory damages is received or accrued by a taxpayer during a taxable year as the result of an award in a civil action for infringement of a patent issued by the United States, then the tax attributable to the inclusion of such amount in gross income for the taxable year shall not be greater than the aggregate of the increases in taxes which would have resulted if such amount had been included in gross income in equal installments for each month during which such infringement occurred.