Despite national outrage after shooters massacred 26 people at a Connecticut elementary school and 12 moviegoers in Colorado, Senate gun-rights supporters in April blocked new efforts to limit gun sales nationwide. Besides killing a ban on assault-style weapons, senators also blocked a proposal to expand background checks on gun purchasers, which polls showed had broad public support. Meanwhile, 20 states enacted laws expanding gun rights so far this year, while nine states passed laws strengthening gun controls. President Obama has begun implementing nearly two dozen executive actions to help reduce gun violence. Although fewer Americans own guns, — the number of firearms has risen 50 percent in 20 years — a trend that accelerated this winter as consumers rushed to buy guns in expectation of possible new federal restrictions. Currently, about 300 million firearms are in circulation in the United States, but those are owned by only one-third of the nation's households.