For those who haven't heard of en_DK before, it's the "European English" (for want of a better description) locale.
It uses Commonwealth English (en_GB) for strings and ISO-14651-1 for collates.
Dates are in YYYY-MM-DD, time is in 24h HH:MM format, Monday is the first day of the week, comma is the decimal separator, currency is euro and standard paper size is A4.
Here in Canada, we're supposed to use spaces to avoid confusion with French or English decimal markers. But actual use of spaces is very rare.
Wiki sez: "[...] officially endorsed by SI/ISO 31-0 standard, as well as by the International Bureau of Weights and Measures and the International Union of Pure and Applied Chemistry (IUPAC), the American Medical Association's widely followed AMA Manual of Style, and the Metrication Board, among others."
@mpjgregoire @erkin @ng0 In Swedish, we use comma for decimal separation and non breaking space as thousands separator, in some special cases replaced by a full stop. There is no consensus about the use of thousands separator in four digit numbers. In numbers less than one, we always write (and pronounce) the zero. The same is true for Norwegian (both of them) and Danish too, except Danish always uses the full stop as thousands separator.