A decade ends and another begins. There is nothing fundamentally notable about a change in decade other than the numerical shift in the calendar. Yet decades are used to define periods of change for such things as fashion style and athletic achievements. For investment purposes, decades are useful as periods of enough length to capture trends. Unless, of course, notable trends begin and end mid-decade. For the seven full decades of the post-World War II period, data is available for many economic and financial measures. A review of some key measures can provide context for investment activity as the decade of the 2020s begins.