spoken by a greater number of people. It is not easily classified and may constitute an independent branch of Tibeto-Burman. Nepali speakers constituted some 40% of the population . The larger minority languages are Dzala (11%), Limbu (10%), Kheng (8%), and Rai (8%). There are no reliable sources for the ethnic or linguistic composition of Bhutan, so these numbers do not add up to 100%. Health Bhutan has a life expectancy of 70.2 years (69.9 for males and 70.5 for females) according to the latest data for 2016 from the World Bank. Basic healthcare in Bhutan is free, as provided by the Constitution of Bhutan. Education Historically, education in Bhutan was monastic, with secular school education for the general population introduced in the 1960s. The mountainous landscape poses barriers to integrated educational services. Today, Bhutan has two decentralised universities with eleven constituent colleges spread across the kingdom. These are the Royal University of Bhutan and Khesar Gyalpo University of Medical Sciences, respectively. The first five-year plan provided for a central education authority—in the form of a director of education appointed in 1961—and an organised, modern school system with free and universal primary education. Education programmes were given a boost in 1990, when the Asian Development Bank (see Glossary) granted a US$7.13 million loan for staff training and development, specialist services, equipment and furniture purchases, salaries and other recurrent costs, and facility rehabilitation and construction at Royal Bhutan Polytechnic. Since the beginning of modern education in Bhutan, teachers from India—especially Kerala—have served in some of the most remote villages of Bhutan. Thus, 43 retired teachers who had served for the longest length of time were personally invited to Thimphu, Bhutan during the Teachers' Day celebrations in 2018, where they were honoured and individually thanked by His Majesty Jigme Khesar Namgyel Wangchuck. To celebrate 50 years of diplomatic relations between Bhutan and India, Bhutan's Education Minister, Jai Bir Rai, honoured 80 retired teachers who served in Bhutan at a special ceremony organised at Kolkata, India, on 6 January 2019. Currently, there are 121 teachers from India placed in schools across Bhutan. Culture Bhutan has a rich and unique cultural heritage that has largely remained intact because of its isolation from the rest of the world until the mid-20th century. One of the main attractions for tourists is the country's culture and traditions. Bhutanese tradition is deeply steeped in its Buddhist heritage. Hinduism