<P> The state is inhabited by 16 tribes--Angami, Ao, Chakhesang, Chang, Kachari, Khiamniungan, Konyak, Kuki, Lotha, Phom, Pochury, Rengma, Sangtam, Sumi, Yimchunger, and Zeme - Liangmai (Zeliang) Each tribe is unique in character with its own distinct customs, language and dress . </P> <P> Two threads common to all are language and religion . English is the official language, the language of education, and spoken by most residents . Nagaland is one of three states in India where the population is mostly Christian . </P> <P> Nagaland became the 16th state of India on 1 December 1963 . Agriculture is the most important economic activity and the principal crops include rice, corn, millets, pulses, tobacco, oilseeds, sugarcane, potatoes, and fibres . Other significant economic activity includes forestry, tourism, insurance, real estate, and miscellaneous cottage industries . </P> <P> The state has experienced insurgency, as well as inter-ethnic conflict since the 1950s . The violence and insecurity have long limited Nagaland's economic development, because it had to commit its scarce resources to law, order, and security . </P>

When did nagaland became a state of india