also announced that after the currency redenomination on 20 August, old banknotes with a face value of 1,000 Bs.F or higher would circulate in parallel with bolívar soberano notes and would continue to be used for a limited time, and that banknotes with a face value below 1,000 Bs.F would be withdrawn from circulation and cease to be legal tender. Immediately following the introduction of the bolívar soberano, the inflation rate increased from 61,463% on 21 August to 65,320% on 22 August. By 24 August 2018, the introduction of the bolívar soberano had not prevented hyperinflation. According to economist Steve Hanke, between 18 August and 21 August 2018, the inflation rate increased from 48,760% to 65,320%. On 22 August, DolarToday estimated that the free-market exchange rate was 71.2 Bs.S per USD. AirTM's reported exchange rate was 75.6 Bs.S per USD. According to DolarToday, the estimated exchange rate was 2700 Bs.S per USD in Venezuela's free market . AirTM's exchange rate was 2200 Bs.S per USD. Introduction of larger banknotes By June 2019, further inflation of the bolívar soberano since redenomination had resulted in 10,000, 20,000, and 50,000 Bs.S banknotes entering circulation effective on 13 June. The BCV stated that the introduction of the new banknotes will "make the payment system more efficient and facilitate commercial transactions." The highest denomination banknote (Bs.S 50,000) was worth US$8 on the black market and was more than the monthly minimum wage of Bs.S 40,000. On 14 June, the BCV estimated the official exchange rate to be 6,244 Bs.S per USD. DolarToday estimated the free market exchange rate to be 6,803 Bs.S per USD. By mid-August 2019, the exchange rate reached an all-time high of 13,921 Bs.S per USD, while the euro was at 15,515 Bs.S per EUR. According to Venezuelan economist Luis Oliveros, the exchange rate experienced "a 30,000% increase" compared to the rate one year ago, 37 Bs.S per USD. By the end of the month, the parallel exchange rate reached nearly 23,000 Bs.S per USD. However, the exchange rate appreciated to about 20,000 Bs.S per USD by 10 October 2019 Informal dollarization Following increased international sanctions throughout 2019, the Maduro government abandoned policies established by Chávez such as price and currency controls (imposed since 2003) which resulted in the country seeing a rebound from economic decline. According to a survey by economic consultant Econalítica, about 54% of transactions in Venezuelan during September