Including the earliest years of the twentieth century has little effect at today's valuations and only a moderate effect at typical valuations. (early-retirement-planning-insights.com)
A «snap back» to more typical valuations is likely, and could negatively impact projected returns for years to come. (theretirementmanifesto.com)
(In the discussions below I mostly show typical valuation levels and total returns versus the volatility in inflation. (hussman.net)