Kerala historically known as Keralam, is a state in South India on the Malabar coast. It was formed on 1 November 1956 following the States Reorganisation Act by combining Malayalam-speaking regions. Spread over 38,863 km2 (15,005 sq mi), it is bordered by Karnataka to the north and northeast, Tamil Nadu to the east and south, and the Lakshadweep Sea to the west. With 33,387,677 inhabitants as per the 2011 Census, Kerala is the thirteenth largest state by population and is divided into 14 districts with the capital being Thiruvananthapuram. Malayalam is the most widely spoken and the official language of the state. The region has been a prominent spice exporter since 3000 BCE. The Chera Dynasty was the first prominent kingdom based in Kerala, though it frequently struggled against attacks by the neighbouring Cholas and Pandyas. In the 15th century, the spice trade attracted Portuguese traders to Kerala, and paved the way for the European colonisation of India. After independence, Travancore and Cochin joined the Republic of India and Travancore-Cochin was given the status of a state in 1949. In 1956, Kerala state was formed by merging Malabar district, Travancore-Cochin (excluding four southern taluks), and the taluk of Kasargod, South Kanara. Kerala has the lowest positive population growth rate in India, 3.44%; highest Human Development Index (HDI), 0.790 in 2011; the highest literacy rate, 93.91% in the 2011 census; the highest life expectancy, 77 years; and the highest sex ratio, 1,084 women per 1000 men. The state has witnessed significant emigration, especially to Arab states of the Persian Gulf during the Gulf Boom of the 1970s and early 1980s, and its economy depends significantly on remittances from a large Malayali expatriate community. Hinduism is practised by more than half of the population, followed by Islam and Christianity. The culture is a synthesis of Aryan and Dravidian cultures, developed over millennia, under influences from other parts of India and abroad.