America will have 2.5 million drones by the end of this year and the number will increase to seven million by 2020, the Federal Aviation Administration (FAA) said in a report release Thursday. While the number of hobby drones is expected to reach from 1.9 million in 2016 to 4.3 million by 2020, commercial drones will see a four times rise from 600,000 to 2.7 million in 4 years. "Unmanned aircraft systems will be the most dynamic growth sector within aviation," the agency said in the report. But it also added that future security and regulatory measures by the U.S. government will be deciding factor on the way civilian drone market grows. In December, the FAA brought in set of rules which stated that registration of small unmanned aircraft weighing more than 0.55 pounds and less than 55 pounds, including payloads such as on-board cameras, was necessary.