The Israel Defence Forces (IDF) have traditionally been a supplier of highly skilled engineers to the R&D labour force, e.g. in electro-optics, radio-frequency engineering, computer science, information technology, cryptography, applied mathematics, industrial management, human resources, system integration and project management. In 2008, the US Patent and Trademark Office issued 1 496 patents to Israeli inventors, corresponding to 208 patents per million inhabitants. By comparison, OECD countries patent at a rate of 43 per million inhabitants per year (this does not include patents issued in Europe and Japan to Israeli inventors).