CNN  —  Despite a surge in hiring last year, air traffic control stations nationwide are still about 3,000 controllers short, according to new Federal Aviation Administration numbers. The numbers show the challenge of filling the gap that led to flight delays and concerns that fatigue contributed to a series of near collisions on runways last year. The shortage is a concern of airlines, controllers, and watchdogs like the inspector general who last summer concluded the agency “made limited efforts to ensure adequate controller staffing at critical air traffic control facilities.” The FAA has about 11,500 controllers who are either fully certified or have reached the stage in training where they can work independently, known as Certified Professional Controller In Training. The staffing plans developed by the FAA and the union representing air traffic controllers calls for more than 14,600 controllers to fully staff towers and centers. The numbers are for the fiscal year, which was through the end of September. Employees in the developmental stage or at the FAA’s training academy are not included in either count. Last year, the FAA hired 1,512 new controller candidates — just above its goal of 1,500, the numbers indicate. The FAA told CNN it “has taken several actions” to address the shortage and improve safety. But at the same time, its air traffic control organization lost more than 1,300 employees, including controllers who retired or candidates who dropped out of training. About 400 failed out of the FAA’s academy (which averages a pass rate of between 60% and 70%) and another 109 who were further along in the training pipeline also dropped out. The numbers suggest this hiring round netted about 160 workers, which was more successful than the previous hiring cycle. The union president representing air traffic controllers said that after accounting for departures, the agency netted an increase of only six new controllers that year. The FAA is aiming to hire 1,800 controllers in the current year, which ends in September. The major aviation policy bill that passed the Senate and is awaiting a House vote requires the agency to maximize hiring for the next several years. It also instructs the FAA to install additional simulators at air traffic control sites to speed up training progress. The current understaffing means controllers at many facilities are regularly working overtime to cover gaps. Administrator Mike Whitaker just last month ordered the agency to increase minimum rest standards, up to as little as 10 hours off between shifts.