Inflation, in an economy that is growing, is caused by more money being introduced into circulation by the central bank. If the amount of tender remains constant, a currency "grows or falls" at the rate of the reserves that back it. The global prevalence of fractional reserve banking has caused most currencies to decline in value consistently. In a non-fractional (fully backed) reserve system, the growth of a currency is equal to the growth (or decline) of the assets backing it, fees are charged in an upfront manner, and money is worth by what it is backed.