Re: the key words "figures in billions"
"What's next, changing the gallon to be a mere 3.8 litres?"
You mean changing it back to 3.8l? English measures changed over time. US ones were crystallized at a point in time, using the Queen Anne 1706 gallon of 231 cubic inches. In the 19th century Britain redefined the gallon to be more capacious (but complicated, roughly 277.274 cubic inches, and based on distilled water at specific air pressure and temperature), and then only in 1976 was it standardized as 277.4194 cubic inches.