Assertions that virtual payments and currencies are on the verge of displacing greenbacks may be premature. More greenbacks are now in circulation than at any time in recent history. Since January 2006, the amount of United States currency in circulation rose about 64 percent, to $1.2 trillion. But at the same time, cash transactions are declining as consumers rely more on debit and credit cards, suggesting that demand for dollars may be driven by hoarders rather than spenders. Americans are also writing half as many checks as they did a decade ago. The number of bank branches, however, has remained relatively stable.