have been reported. Science and technology Thailand ranked 43rd in the Global Innovation Index in 2021. The Ministry of Higher Education, Science, Research and Innovation and its agencies oversees the development of science, technology, and research in Thailand. According to the National Research Council of Thailand, the country devoted 1.1% of its GDP to the research and development of science in 2019, with over 166,788 research and development personnel in full-time equivalent that year. Infrastructure Transportation The State Railway of Thailand (SRT) operates all of Thailand's national rail lines. Bangkok Railway Station (Hua Lamphong Station) is the main terminus of all routes. Phahonyothin and ICD Lat Krabang are the main freight terminals. SRT had of track, all of it meter gauge except the Airport Link. Nearly all is single-track (4,097 km), although some important sections around Bangkok are double () or triple-tracked () and there are plans to extend this. Rail transport in Bangkok includes long-distance services, and some daily commuter trains running from and to the outskirts of the city during the rush hour, but passenger numbers have remained low. There are also three rapid transit rail systems in the capital. Thailand has of highways. , Thailand has over 462,133 roads and 37 million registered vehicles, 20 million of them motorbikes. A number of undivided two-lane highways have been converted into divided four-lane highways. There are 4,125 public vans operating on 114 routes from Bangkok alone. Other forms of road transport includes tuk-tuks, taxis—with over 80,647 registered taxis nationwide as of 2018—vans (minibus), motorbike taxis and songthaews. , Thailand has 103 airports with 63 paved runways, in addition to 6 heliports. The busiest airport in the country is Bangkok's Suvarnabhumi Airport. Energy 75% of Thailand's electrical generation is powered by natural gas in 2014. Coal-fired power plants produce an additional 20% of electricity, with the remainder coming from biomass, hydro, and biogas. Thailand produces roughly one-third of the oil it consumes. It is the second largest importer of oil in SE Asia. Thailand is a large producer of natural gas, with reserves of at least 10 trillion cubic feet. After Indonesia, it is the largest coal producer in SE Asia, but must import additional coal to meet domestic demand. Demographics Thailand had a population of 69,799,978 as of 2020. Thailand's population is largely rural, concentrated in the rice-growing areas of the central, northeastern and northern regions. About 45.7% of