Mumbai, Aug 29: The detection of counterfeit notes in the Rs 50 and Rs 100 denomination witnessed a record high in 2017-18 compared with two preceding fiscals, the RBI announced on Wednesday.According to the Reserve Bank of India's (RBI) annual report for 2017-18, the number of fake Rs 50 notes detected shot up 154.3 per cent to 23,447 pieces, as against 9,222 notes detected in 2016-17 and 6,453 in 2015-16.The RBI said that the detection of counterfeit Rs 100 notes increased 35 per cent to 239,182 pieces during the said period, compared with 177,195 notes in 2016-17 and 221,447 in 2015-16.However, the detection of counterfeit notes was 31.4 per cent lower in 2017-18 compared with the previous year. "Counterfeit notes in denominations of Rs 500 and Rs 1,000 detected in SBNs (specified banknotes) decreased by 59.7 and 59.6 per cent respectively, as the same comprised only the residual part of SBN deposits processed during 2017-18," the report said.This "residual" currency refers to the high-value notes scrapped by demonetisation in November 2016. "During 2017-18, as many as 522,783 pieces of counterfeit notes were detected in the banking system, of which 63.9 per cent were detected by banks other than the Reserve Bank," the RBI said. Moreover, out of the total fake notes detected at the RBI, their share during 2017-18 was higher at 36.1 per cent, compared with 4.3 per cent during the previous year. This was because of processing of a large volume of SBNs withdrawn from circulation by demonetisation, the report said. Speaking of the Indian economy, the annual report said that there are upside risks to inflation which requires vigilance.Pointing out that while headline inflation is likely to face upside risks over the remaining period of the current fiscal, the RBI projected the country's real Gross Domestic Product for the same period to grow to 7.4 per cent from 6.7 per cent in the previous year. India's central bank also said that credit growth is likely to be supported by the progress in resolving the most pressing problem of non-performing assets, or bad loans, under the Insolvency and Bankruptcy Code, 2016.