RBI on Wednesday said the cost of printing notes doubled to ₹7,965 crore in 2016-17 from ₹3,421 crore in 2015-2016, on account of new currency printing post demonetisation. RBI said 7.62 lakh counterfeit currency notes were detected in 2016-17. It further said that 8.9 crore old ₹1,000 notes out of 632.6 crore didn't come back to the system.