A non-governmental organization (NGO) is an organization that is neither a part of a government nor a conventional for-profit business. Usually set up by ordinary citizens, NGOs may be funded by governments, foundations, businesses, or private persons. Some avoid formal funding altogether and are run primarily by volunteers. NGOs are highly diverse groups of organizations engaged in a wide range of activities, and take different forms in different parts of the world. Some may have charitable status, while others may be registered for tax exemption based on recognition of social purposes. Others may be fronts for political, religious, or other interests. The number of NGOs in the United States is estimated at 1.5 million. Russia has 277,000 NGOs. India is estimated to have had around 2 million NGOs in 2009, just over one NGO per 600 Indians, and many times the number of primary schools and primary health centers in India. NGOs are difficult to define, and the term 'NGO' is rarely used consistently. As a result, there are many different classifications in use. The most common focus is on "orientation" and "level of operation".