Translation: The energy efficiency of computers doubles roughly every 18 months.
In a new twist beyond Moore’s Law, which shows signs of reaching it’s limits, there’s Koomey’s Law. In his own words, the idea is:
“…at a fixed computing load, the amount of battery you need will fall by a factor of two every year and a half.”
Why does this matter? It means we can fit more more computing power into smaller and smaller devices. Which is much of the reason the phone in your pocket is probably more powerful than the EDVAC there in the chart.