What this shows. The upper panel is Robert Shiller's cumulative real (inflation-adjusted) total return on long-term U.S. Treasury bonds, monthly since January 1871, rebased to 1.0 at the start and plotted on a log scale — the same series used in the Shiller ie_data.xls data set (Real Total Bond Returns).

Subsequent 10-year real return (lower panel)

Each point is the annualised real return of the ten-year window ending on that date — the subsequent-ten-year return of the decade that began ten years earlier, plotted as it completes: (Index[t] ÷ Index[t−120m])^(1/10) − 1. That convention keeps the line running to the present, so both panels share the same dates end-to-end (latest window ends —). The 1971–1981 decade delivered about −5.4%/yr real; the 1981–1991 decade about +11%/yr.

Event rules

Dashed verticals mark regime dates: WWI (U.S. entry, Apr 1917), WWII (Pearl Harbor, Dec 1941), Bretton Woods/Volcker (Nixon closes the gold window, Aug 1971 — followed by the Volcker disinflation), and Covid-19 (Mar 2020).

Data & updates

Source: Robert J. Shiller, ie_data.xls, served live from shillerdata.com (the legacy econ.yale.edu copy froze in Sep 2023). A cron job refreshes treasury-secular-data.json daily and re-embeds it as an offline fallback. Shiller's file updates monthly with a short lag. Not investment advice.