can swim. The Public Health Ministry said that from 2006 to 2015, 10,923 children drowned. Of the 8.3 million children aged 5–14 nationwide, only two million can swim, according to the Public Health Ministry. The United Nations classifies Thailand as an "aging society" (one-tenth of the population above 60), on track to become an "aged society" (one-fifth of the population above 60) by 2025. The Fiscal Policy Office projects that the number of Thais aged 60-plus will increase from 14 percent in 2016 to 17.5 percent in 2020, 21.2 percent in 2025, and 25.2 percent in 2030. it is estimated that there are 94,000 employees aged 60 years or more in the workforce. Ethnic groups Thailand's ethnic origins are diverse and continue to evolve. The nation's ethnic makeup is obscured by the pressures of Thaification, Thai nationalism, and social pressure, which is intertwined with a caste-like mentality assigning some groups higher social status than others. In its report to the United Nations for the International Convention on the Elimination of All Forms of Racial Discrimination, the Thai government officially recognized 62 ethnic communities. Twenty million Central Thai (together with approximately 650,000 Khorat Thai) make up approximately 20,650,000 million (34.1 percent) of the nation's population of 60,544,937 at the time of completion of the Mahidol University Ethnolinguistic Maps of Thailand data (1997). Thailand's report to the UN provided population numbers for mountain peoples and ethnic communities in the northeast. Thus, though over 3.288 million people in the northeast alone could not be categorised, the population and percentages of other ethnic communities c. 1997 are known and constitute minimum populations. In descending order, the largest (equal to or greater than 400,000) are a) 15,080,000 Lao (24.9 percent) consisting of the Thai Lao (14 million) and other smaller Lao groups, namely the Thai Loei (400-500,000), Lao Lom (350,000), Lao Wiang/Klang (200,000), Lao Khrang (90,000), Lao Ngaew (30,000), and Lao Ti (10,000); b) six million Khon Muang (9.9 percent, also called Northern Thais); c) 4.5 million Pak Tai (7.5 percent, also called Southern Thais); d) 1.4 million Khmer Leu (2.3 percent, also called Northern Khmer); e) 900,000 Malay (1.5%); f) 500,000 Nyaw (0.8 percent); g) 470,000 Phu Thai (0.8 percent); h) 400,000 Kuy/Kuay (also known as Suay) (0.7 percent), and i) 350,000 Karen (0.6 percent). Thailand's Ministry of Social Development and Human Security's 2015 Master Plan for the Development of Ethnic Groups in Thailand