That’s not accurate. If you look at the article that image is used in[0], you’ll see that while only 24% of the world’s population uses a comma, 60% uses a full stop. So while yes, it’s pretty much ubiquitous in Europe, worldwide 2.5x more people use the full stop.
Luckily, grouping by 3 digits and typically only displaying 2 decimal places makes it easy to determine the intended number based on context.
I would argue that percentage of population that uses one versus the other is not the best metric here to determine worldwide use, but rather geographic dispersion or likelihood of use in a random international communication. The parent comments were discussing the appropriateness of the comma/period as decimal on HN, as a forum of generally international interest. As such, sheer percentage of users is not as relevant as the accepted usage in an international or intercultural context. We end up being in agreement over the outcome, but disagree on the standard for measurement.
Example of why percentage population doesn't work: 14% of the world speaks Chinese natively by one estimate, the most of any language. [1] Does that mean that Chinese punctuation or syntactic standards are more likely to be used worldwide?
I like your Chinese example because it made me think about the root question, but I think there’s an important distinction to be made in that while only a plurality of people speak Chinese natively (and a small one at that, less that 1 of every 5 people), a majority of people use the full stop decimal notation (and a decently large one at that, 3 of every 5).
If you pick a language at random, it is more likely to not be Chinese than it is to be Chinese, but it is more likely to be Chinese than any other single language. However, if you pick a notation at random it is both more likely to be full stop than any other notation as well as more likely to be full stop than any other specific notation (I believe the chart only showed three examples). I didn’t take the time to look into it but it also appears that weighting each country equally (e.g. Luxembourg = China for probability’s sake) would shift the balance in favor of comma notation, which may belie more cultural or regional significance than simply focusing on the population percentage.
I would argue it's not _most_ parts of the world (imo roughly half) [0]. But surely it is a better idea to use comma here as the sentence is in English.
I had to spend an hour explaining our comma system to a friend that happens to be a translator. It's very difficult for people outside the US to understand our notation system.
"We use commas to divide large integers into groups of 3 digits. Grouping is done from the right end of the number, for example: 17,000,120".
Those two rules are, to my knowledge, the entirety of the US number-commaing system. How did you spend an hour on it? It might be difficult for people to understand it before having it explained, but I wouldn't call it complex.
She just couldn't wrap her head around it. Kept going back and forth. She was trying to determine whether a number in a document she was translating meant million or billion.
The main difference is that the English-speaking world mainly uses the comma, and HN is generally an English-language board.
[1]: http://en.wikipedia.org/wiki/File:20130228DecimalSeparator.s...