In December, inflation dropped again and retail sales roared again. Growth without almost no inflation is an optimal condition, rare in modern U.S. history. Meanwhile, earnings growth is accelerating and earnings drive stocks.

Drilling into the retail sales figures, in the 12 months through December, online sales grew explosively and non-store retail sales shot up 12.2%.

Dominated by Amazon, non-store retail sellers have reshaped the way American consumers spend. Department stores are shuttering locations.