punctuation - Commas in "The chart shows information about how many people worked from home, in the USA and UK, between 2005 and 2010."

So I've got this sentence in my IELTS prep book:

The chart shows information about how many people worked from home, in
the USA and UK, between 2005 and 2010.

The commas sound so weird. I would be grateful if somebody could explain what are they doing up there.

Actually, the following sentence looks similar but doesn't contain commas:

The chart highlights data about the amount of electricity which was consumed in India and Pakistan between 2004 and 2010.

What is going on?

Answer

Personally, I would read the first sentence as indicating that the chart showed separately how many people worked from home in the UK, and also showed how many worked from home in the USA. If the first comma were omitted, I would expect to see a chart showing only the total from both countries combined.

The way the second example is written, I would expect to see only the combined electrical usage of the two countries. If I were describing a chart showing the electrical usage of each, I might say "which was consumed in India and in Pakistan..."

This may or may not be what the author intended, but I believe the meanings are clearer when commas are used in this way and that leaving them out entirely would change the meaning.

Commas are much more than mere optional style. The Panda famously, "Eats, shoots, and leaves."