I wonder if the U.S. is the best team based on fans per capita. Sure, we have 320 million citizens, but certainly much fewer fans (less than 5 mil). Would that makes us the greatest team in the WC?
Do you people not understand what per capita means? Meaning, if the US has 320 million people and 10 million fans, 1 in 32 is a soccer fan. The total population of a Uruguay or Slovenia is irrelevant--Uruguay has 3.3 million people but surely all of them are soccer fans; probably 99 out of 100. Per capita is a way to compare sample groups of different sizes by using ratios.
Fine. I thought he was bragging on the US team on the basis of our small fan base. I don't really see the point in asking after the measurement you're asking after, or even how to compare different quality teams with different proportions of fans. I guess the relevant rivals are Australia, New Zealand, and North Korea. Is the US better than Australia based on fans per capita? Is that something to be proud of, especially given how many more Americans there are than Australians?
I guess the OP is asking what has the highest ratio of team success to fan investment (the success per shits given ratio). It's kind of a fun question. Of course, to get a useful SPSG ratio, we'd also have to be able to quantify not only the number of fans but the degree and kind of their investment. How intensely do they care, and how do they care (positively, negatively, loudly, quietly, dancing-ly, etc.)? After all it might be useful to distinguish between support and interest. Some teams get a lot of interest from their fans (and press), but I'm not sure I'd call it support. An interesting related question: what nation has the lowest SPSG?