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Note 9 - Federal Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Tax at statutory rate, amount | $ 20,640 | $ 21,567 | $ 15,915
Tax at statutory rate, percent | 21.00% | 21.00% | 21.00%
Tax-exempt interest, amount | $ (1,027) | $ (862) | $ (695)
Tax-exempt interest, percent | (1.00%) | (0.80%) | (0.90%)
Bank owned life insurance, amount | $ (529) | $ (303) | $ (334)
Bank owned life insurance, percent | (0.50%) | (0.30%) | (0.40%)
Non-deductible expenses, amount | $ 241 | $ 213 | $ 129
Non-deductible expenses, percent | 0.20% | 0.20% | 0.20%
Tax credits, amount | $ (266) | $ 24 | $ (262)
Tax credits, percentage | (0.30%) | 0.00% | (0.30%)
Other, amount | $ (366) | $ (157) | $ (26)
Other, percent | (0.40%) | (0.20%) | 0.00%
Tax expense | $ 18,693 | $ 20,482 | $ 14,727
Tax expense, percent | 19.00% | 19.90% | 19.60%

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