Part of the strength of Ottawa’s economy is the diversity of its industries. Ottawa’s knowledge-based sectors continue to grow employing over 75,000 employees within 1,922 companies. The Knowledge Based Support Services sector is the largest with 570 companies established in the community followed by the software sector with a total of 362 companies in the region. The Aerospace and Defence, eBusiness, Telecommunications and Cleantech industries also have a significant impact in Ottawa's high tech sector with a total of 609 companies between them. Although the Knowledge-Based Support Services industry employs the largest number of people, the Telecommunications sector follows closely and has the second largest employer. The Software and Aerospace and Defence sectors also play a hefty role in the community, employing 23,155 people between them. IBM is now Ottawa’s largest employer outside of the public sector. Supported by a strong professional services cluster, Ottawa's economy is complemented by a vibrant tourism sector and the presence of more than 110,000 government employees. With the highest level of R&D spending per capita in the country, the Ottawa region has become the home of leading economic clusters. An economic powerhouse with a quality of life second to none, Ottawa is one of North America's fastest growing economies, and one of the world's most progressive centres of innovation. In partnership with the City of Ottawa, Invest Ottawa has identified six key sectors that demonstrate the greatest potential for growth: Wireless, Photonics, Defence and Security, Cleantech, Life Sciences,  and Film, Digital Media and Television Production.