irs 2018 tax tables deductions 1040 tax and earned income credit irs schedule eic 1040 form pdffiller 2018 form irs publication 596 fill eic frequently asked questions eic earned income tax credit the earned income tax credit eitc earned income credit eic irs 1040 schedule eic 2019 fill and 2018 earned income tax credit 3 limits 1040 2023 internal revenue service 2001 earned income credit eic table