The number of U.S. jobs in solar energy overtook those in oil and natural gas extraction for the first time last year, helping drive a global surge in employment in the clean-energy business as fossil-fuel companies faltered. Employment in the U.S. solar business grew 12 times faster than overall job creation, the International Renewable Energy Agency said in a report on Wednesday. About 8.1 million people worldwide had jobs in the clean energy in 2015, up from 7.7 million in 2014, according to the industry group based in Abu Dhabi.