By 2012, the USMC reported fleetwide readiness rate had risen to 68 percent; however, the DODs Inspector General later found 167 of 200 reports had "improperly recorded" information. Captain Richard Ulsh blamed these errors on incompetence and said that they were "not malicious" or deliberate. The required mission capable rate was 82%, but the average was 53% from June 2007 to May 2010. In 2010, Naval Air Systems Command aimed for an 85% reliability rate by 2018. From 2009 to 2014, readiness rates rose 25 percent to the "high 80s", while operating cost had dropped 20 percent to $9,520 through a rigorous maintenance improvement program that focused on diagnosing problems before failures occur. , although the V-22 requires higher maintenance and has lower availability (62%) than traditional helicopters, it also has a lower incidence rate. The average cost per flight hour is , whereas the Sikorsky CH-53E Super Stallion cost about $20,000 per flight hour in 2007. V-22 Total cost of ownership was $83,000 per hour in 2013.
Question: How many years was the time span where was the average mission capable rate 53%
Answer: 3; 3