The statistic comes from the "G4S World Cash Report", published in April, 2018.
According to the World Cash Report, currency in circulation (CIC) rose by 46% across Asia from 2011 to 2016. CIC measures the total amount of cash held by the public, including businesses, banks and consumers.
Excerpt from report
"The amount of currency in circulation (CIC, local currencies) is on the rise in all countries in Asia in absolute terms, with an increase of 45.6% over the past 5 years, or 9.1% on average per annum." (G4S 2018, p. 46)
