Three years after Japan closed all of its nuclear plants in the wake of the Fukushima meltdown and Germany decided to shut its industry, developing countries are leading the biggest construction boom in more than two decades.

Almost two-thirds of the 70 reactors currently under construction worldwide, the most since 1989, are located in China, India, and the rest of the Asia-Pacific region. Countries including Egypt, Bangladesh, Jordan and Vietnam are considering plans to build their first nuclear plants, according to Bloomberg New Energy Finance in London. Developed countries are building nine plants, 13 percent of the total.

Power is needed as the economies of China and India grow more than twice as fast as the U.S. Electricity output from reactors amounted to 2,461 terawatt-hours last year, or 11 percent of all global power generation, according to data from the Organization for Economic Cooperation and Development and the International Energy Agency. That's the lowest share since 1982, the data show.