Albania, Andorra, Argentina, Austria, Azerbaijan, Belarus, Belgium,
Bolivia, Bosnia and Herzegovina, Brazil, Bulgaria, Cameroon, Canada
(French-speaking), Costa Rica, Croatia, Cuba, Chile, Colombia, Cyprus,
Czech Republic, Denmark, Dominican Republic, Ecuador, El Salvador,
Estonia, Faroes, Finland, France, Germany, Greece, Greenland,
Guatemala, Honduras,Hungary, Indonesia, Iceland, Italy, Latvia,
Lithuania, Luxembourg (uses both separators officially), Macedonia,
Moldova, Netherlands, Norway, Nicaragua, Panama, Paraguay, Peru,
Poland, Portugal, Romania, Russia, Serbia, Slovakia, South Africa
(officially, but dot point is commonly used in business and science),
Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine, Uruguay,
Venezuela, Vietnam
See
http://en.wikipedia.org/wiki/Decimal_separator
Why? There is nothing sacred or even correct about the US usage of
these symbols. Any other symbols would do just as well. If some
country decided to write 1*000*000&00, instead of 1,000,000.00 or
1.000.000,00, that would be fine. The symbols are arbitrary, and any
particular set is just as good as any other.