{
  "version": "income-tax-history.v1",
  "publishedAt": "2026-09-01T22:30:00Z",
  "coverage": {
    "status": "partial",
    "taxYears": [2025, 2026],
    "jurisdictions": ["CO", "CT", "IA", "ID", "KY", "NJ", "RI", "VT"],
    "note": "This is a partial, receipt-bound history series, not a complete 2025 state snapshot. A point is published only when its tax year and comparable field definition are explicit in an official source."
  },
  "points": [
    {
      "code": "CO",
      "name": "Colorado",
      "taxYear": 2025,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [{ "floor": 0, "rate": 0.044 }],
      "topMarginalRate": 0.044,
      "topBracketFloor": 0,
      "source": {
        "field": "rateScheduleScope",
        "url": "https://tax.colorado.gov/sites/tax/files/documents/Book104_2025.pdf",
        "asOf": "2026-08-15",
        "type": "official-dor",
        "sourceYear": 2025
      }
    },
    {
      "code": "CT",
      "name": "Connecticut",
      "taxYear": 2025,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [
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        { "floor": 10000, "rate": 0.045 },
        { "floor": 50000, "rate": 0.055 },
        { "floor": 100000, "rate": 0.06 },
        { "floor": 200000, "rate": 0.065 },
        { "floor": 250000, "rate": 0.069 },
        { "floor": 500000, "rate": 0.0699 }
      ],
      "topMarginalRate": 0.0699,
      "topBracketFloor": 500000,
      "source": {
        "field": "brackets (2025 Tax Calculation Schedule)",
        "url": "https://portal.ct.gov/-/media/drs/forms/2025/income/ct-1040-tcs_1225.pdf",
        "asOf": "2026-08-05",
        "type": "official-dor",
        "sourceYear": 2025
      }
    },
    {
      "code": "IA",
      "name": "Iowa",
      "taxYear": 2025,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [{ "floor": 0, "rate": 0.038 }],
      "topMarginalRate": 0.038,
      "topBracketFloor": 0,
      "source": {
        "field": "2025 individual income-tax rate",
        "url": "https://revenue.iowa.gov/press-release/2024-10-16/idr-announces-2025-individual-income-tax-brackets-and-interest-rates",
        "asOf": "2026-09-01",
        "type": "official-dor",
        "sourceYear": 2025
      }
    },
    {
      "code": "ID",
      "name": "Idaho",
      "taxYear": 2025,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [
        { "floor": 0, "rate": 0 },
        { "floor": 4811, "rate": 0.053 }
      ],
      "topMarginalRate": 0.053,
      "topBracketFloor": 4811,
      "source": {
        "field": "brackets",
        "url": "https://tax.idaho.gov/taxes/income-tax/individual-income/individual-income-tax-rate-schedule/",
        "asOf": "2026-08-15",
        "type": "official-dor",
        "sourceYear": 2025
      }
    },
    {
      "code": "KY",
      "name": "Kentucky",
      "taxYear": 2025,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [{ "floor": 0, "rate": 0.04 }],
      "topMarginalRate": 0.04,
      "topBracketFloor": 0,
      "source": {
        "field": "2025 individual income-tax rate",
        "url": "https://revenue.ky.gov/Forms/740%20Packet%20Instructions%20%282025%29.pdf",
        "asOf": "2026-09-01",
        "type": "official-dor",
        "sourceYear": 2025
      }
    },
    {
      "code": "NJ",
      "name": "New Jersey",
      "taxYear": 2025,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [
        { "floor": 0, "rate": 0.014 },
        { "floor": 20000, "rate": 0.0175 },
        { "floor": 35000, "rate": 0.035 },
        { "floor": 40000, "rate": 0.05525 },
        { "floor": 75000, "rate": 0.0637 },
        { "floor": 500000, "rate": 0.0897 },
        { "floor": 1000000, "rate": 0.1075 }
      ],
      "topMarginalRate": 0.1075,
      "topBracketFloor": 1000000,
      "source": {
        "field": "brackets",
        "url": "https://www.nj.gov/treasury/taxation/pdf/current/1040i.pdf",
        "asOf": "2026-08-15",
        "type": "official-dor",
        "sourceYear": 2025
      }
    },
    {
      "code": "RI",
      "name": "Rhode Island",
      "taxYear": 2025,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [
        { "floor": 0, "rate": 0.0375 },
        { "floor": 79900, "rate": 0.0475 },
        { "floor": 181650, "rate": 0.0599 }
      ],
      "topMarginalRate": 0.0599,
      "topBracketFloor": 181650,
      "source": {
        "field": "Uniform tax rate schedule for Tax Year 2025 (Personal Income Tax)",
        "url": "https://tax.ri.gov/sites/g/files/xkgbur541/files/2025-11/ADV_2025_22_Inflation_Adjustments.pdf",
        "asOf": "2026-09-01",
        "type": "official-dor",
        "sourceYear": 2025
      }
    },
    {
      "code": "VT",
      "name": "Vermont",
      "taxYear": 2025,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [
        { "floor": 0, "rate": 0.0335 },
        { "floor": 49400, "rate": 0.066 },
        { "floor": 119700, "rate": 0.076 },
        { "floor": 249700, "rate": 0.0875 }
      ],
      "topMarginalRate": 0.0875,
      "topBracketFloor": 249700,
      "source": {
        "field": "brackets, standard deduction (2025 Vermont Rate Schedules)",
        "url": "https://tax.vermont.gov/sites/tax/files/documents/TaxRateSched-2025.pdf",
        "asOf": "2026-08-05",
        "type": "official-dor",
        "sourceYear": 2025
      }
    },
    {
      "code": "IA",
      "name": "Iowa",
      "taxYear": 2026,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [{ "floor": 0, "rate": 0.038 }],
      "topMarginalRate": 0.038,
      "topBracketFloor": 0,
      "source": {
        "field": "brackets",
        "url": "https://revenue.iowa.gov/press-release/2025-10-21/idr-announces-2026-individual-income-tax-and-interest-rates",
        "asOf": "2026-06-20",
        "type": "official-dor",
        "sourceYear": 2026
      }
    },
    {
      "code": "KY",
      "name": "Kentucky",
      "taxYear": 2026,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [{ "floor": 0, "rate": 0.035 }],
      "topMarginalRate": 0.035,
      "topBracketFloor": 0,
      "source": {
        "field": "2026 individual income-tax rate",
        "url": "https://revenue.ky.gov/Forms/2026%20Withholding%20Formula.pdf",
        "asOf": "2026-06-20",
        "type": "official-dor",
        "sourceYear": 2026
      }
    },
    {
      "code": "RI",
      "name": "Rhode Island",
      "taxYear": 2026,
      "datasetVersion": "income-tax-history.v1",
      "publishedAt": "2026-09-01T22:30:00Z",
      "metricDefinition": "individual-income-tax.single.top-marginal-rate-on-taxable-income.v1",
      "status": "verified",
      "rateSchedule": [
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        { "floor": 82050, "rate": 0.0475 },
        { "floor": 186450, "rate": 0.0599 }
      ],
      "topMarginalRate": 0.0599,
      "topBracketFloor": 186450,
      "source": {
        "field": "Uniform tax rate schedule for Tax Year 2026 (Personal Income Tax)",
        "url": "https://tax.ri.gov/sites/g/files/xkgbur541/files/2025-11/ADV_2025_22_Inflation_Adjustments.pdf",
        "asOf": "2026-06-20",
        "type": "official-dor",
        "sourceYear": 2026
      }
    }
  ]
}