Over 99 per cent of Rs. 500 and Rs. 1,000 notes banned by Prime Minister Narendra Modi in the November 2016 demonetisation have returned to the banking system, the Reserve Bank of India said today after completing what it calls the "humungous task" of counting the banned cash. The central bank's annual report says only a fraction of the currency was left out of the system after the unprecedented notes ban aimed at checking black money and corruption - an exercise that cost the government Rs. 8,000 crore. The opposition Congress promptly said the PM must "apologise" for lying to the nation.