U.S. companies have manufactured more than 70 million firearms since 2008, rapidly escalating the production of pistols and the types of rifles used in recent mass shootings, government and industry data show. In 2016, the latest year for which data is available, production spiked as firearms companies built roughly 11 million guns, in part due to a belief that Democrats would win elections that year and curb access to semiautomatic weapons such as the AR-15 rifle. More than 4 million rifles were produced in 2016, up from 1.8 million in 2010.