In France, the full stop was already in use in printing to make Roman numerals more readable, so the comma was chosen.[11] Many other countries, such as Italy, also chose to use the comma to mark the decimal units position.[11] It has been made standard by the ISO for international blueprints.[12] However, English-speaking countries took the comma to separate sequences of three digits. In some countries, a raised dot or dash (upper comma) may be used for grouping or decimal separator; this is particularly common in handwriting.
In the United States, the full stop or period (.) was used as the standard decimal separator.
The 22nd General Conference on Weights and Measures declared in 2003 that "the symbol for the decimal marker shall be either the point on the line or the comma on the line". It further reaffirmed that "numbers may be divided in groups of three in order to facilitate reading; neither dots nor commas are ever inserted in the spaces between groups". This usage has therefore been recommended by technical organizations, such as the United States' National Institute of Standards and Technology.[21]
ISO-8601 also stipulates normative notation based on SI conventions, adding that the comma is preferred over the full stop. [22]
In 1958, disputes between European and American delegates over the correct representation of the decimal separator nearly stalled the development of the ALGOL computer programming language.[19] ALGOL ended up allowing different decimal separators, but most computer languages and standard data formats (e.g. C, Java, Fortran, Cascading Style Sheets (CSS)) specify a dot.
The groups created by the delimiters tend to follow the use of the local language, which varies. In European languages, large numbers are read in groups of thousands and the delimiter (which occurs every three digits when it is used) may be called a "thousands separator". In East Asian cultures, particularly China, Japan, and Korea, large numbers are read in groups of myriads (10,000s) but the delimiter commonly separates every three digits.[citation needed] The Indian numbering system is somewhat more complex: it groups the rightmost three digits together (till the hundreds place) and thereafter groups by sets of two digits. One trillion would thus be written as 10,00,00,00,00,000 or 10 kharab.[28]
