{
  "@context": "https://schema.org",
  "@type": "Dataset",
  "name": "S&P 500 Annualized Real Returns by Decade (1930-2025)",
  "description": "Inflation-adjusted (CPI-U deflated) annualized total returns for the S&P 500 by calendar decade from 1930 through 2024, plus the 2025 partial decade. Curated by Snowballr from Robert Shiller's CAPE dataset and BLS CPI history.",
  "version": "2026.1",
  "datePublished": "2026-06-08",
  "dateModified": "2026-06-08",
  "publisher": { "name": "Snowballr", "url": "https://snowballr.io" },
  "creator": { "name": "Snowballr Research Team", "url": "https://snowballr.io/editorial-standards" },
  "primarySource": [
    {
      "title": "Online Data Robert Shiller (CAPE)",
      "url": "http://www.econ.yale.edu/~shiller/data.htm",
      "author": "Robert J. Shiller"
    },
    {
      "title": "Consumer Price Index for All Urban Consumers (CPI-U)",
      "url": "https://www.bls.gov/cpi/",
      "publisher": "U.S. Bureau of Labor Statistics"
    }
  ],
  "license": "CC-BY-4.0",
  "citation": "Snowballr (2026). S&P 500 Annualized Real Returns by Decade. https://snowballr.io/data",
  "methodology": "Annualized geometric mean total return (including reinvested dividends) deflated by CPI-U. Decade defined inclusively (e.g., 2000-2009 inclusive = 10 calendar years).",
  "data": [
    { "decade": "1930s", "nominalAnnualizedReturn": -0.0094, "realAnnualizedReturn": 0.0001 },
    { "decade": "1940s", "nominalAnnualizedReturn": 0.0902, "realAnnualizedReturn": 0.0314 },
    { "decade": "1950s", "nominalAnnualizedReturn": 0.1935, "realAnnualizedReturn": 0.1697 },
    { "decade": "1960s", "nominalAnnualizedReturn": 0.0780, "realAnnualizedReturn": 0.0524 },
    { "decade": "1970s", "nominalAnnualizedReturn": 0.0586, "realAnnualizedReturn": -0.0153 },
    { "decade": "1980s", "nominalAnnualizedReturn": 0.1759, "realAnnualizedReturn": 0.1188 },
    { "decade": "1990s", "nominalAnnualizedReturn": 0.1821, "realAnnualizedReturn": 0.1474 },
    { "decade": "2000s", "nominalAnnualizedReturn": -0.0095, "realAnnualizedReturn": -0.0354 },
    { "decade": "2010s", "nominalAnnualizedReturn": 0.1356, "realAnnualizedReturn": 0.1124 },
    { "decade": "2020-2024", "nominalAnnualizedReturn": 0.1416, "realAnnualizedReturn": 0.0892 }
  ],
  "summaryStats": {
    "fullPeriodRealReturn": 0.0689,
    "fullPeriodNominalReturn": 0.1018,
    "worstDecadeReal": "1970s",
    "bestDecadeReal": "1950s",
    "notes": "Real returns are the relevant figure for retirement planning since spending is in real (today's) dollars."
  }
}