The share of cash in 2016 accounted for 12.6 percent of GDP and the forecast includes the share being 11.2 percent by 2021; while new forms of payments are being adopted and card payments still used widely, cash will still play an important role; a few of the main reasons for continued cash usage is people prefer to use cash for small transactions, 27 percent of U.S. consumers are unbanked and fraud has become more widespread which can cause people to use cash more. Source.
