Use decimals and commas for English figures as follows:
General Figures: 22,500 people, 1.5 million cars, 42.8 square meters
Money figures: $4,564.54, $4.5 million, 5.67 billion Turkish lira
Percents: 43.8 percent (in writing), 43.8% (in numbers)
Note: Decimals and commas in Turkish figures are reversed. When translating, you need to be careful in correcting the numbers and aligning them with proper English format.
Dragoman Style Guide for Figures