The lack of an educated workforce skilled in modern technology contributes to the growing problems of the economy.[194] The country lacks adequate infrastructure. Goods travel primarily across the Thai border (where most illegal drugs are exported) and along the Irrawaddy River. Railways are old and rudimentary, with few repairs since their construction in the late 19th century.[195] Highways are normally unpaved, except in the major cities.[195] Energy shortages are common throughout the country including in Yangon and only 25% of the country's population has electricity.