6.5. Punctuation in figures
Serial numbers, for example page numbers, are not grouped in thousands:
In the Official Journal a comma is used to separate whole numbers from decimals for technical purposes to speed up production.
Budgetary data: million or billion
In English use billion to mean 1 000 million (see Section 10.5(d)).
Up to three decimal places, keep to the appropriate unit:
1.326 billion (not 1 326 million)
Above three decimal places, descend to the smaller unit:
1 326.1 million (not 1.3261 billion)
This makes the figures easier to read and compare.