Here we are looking at the Excess CAPE yield for the SPX500 over the last 100+ years
"A higher CAPE meant a lower subsequent 10-year return, and vice versa. The R-squared was a phenomenally high 0.9 — the CAPE on its own was enough to explain 90% of stocks’ subsequent performance over a decade. The standard deviation was 1.37% — in other words, two-thirds of the...
Shiller PE ratio for the S&P 500. Price earnings ratio is based on average inflation-adjusted earnings from the previous 10 years, known as the Cyclically Adjusted PE Ratio (CAPE Ratio)
HOW TO USE
It provide historic Shiller PE which will provide over-bought or over-sold condition historically from 19th century.