Rolls-Royce PLC is the world's second-largest aero-engine manufacturer. Its engines power more than 30 types of commercial aircraft, and it has more 30,000 engines currently in service across both the civil and defence sectors. With a workforce of over 12,000 people, Derby has the largest concentration of Rolls-Royce employees in the UK. Rolls-Royce also produces low-emission power systems for ships; makes critical equipment and safety systems for the nuclear industry and powers offshore platforms and major pipelines for the oil and gas industry. The pharmaceutical industry plays an important role in the UK economy and the country has the third-highest share of global pharmaceutical R&D expenditures.