Definition
Once converted, holdings continue to grow tax-deferred but the holder must withdraw at least the prescribed minimum amount each calendar year, calculated as a percentage of the account's January 1 fair market value. The minimum percentage starts at 5.28% at age 71 and rises to 20% at age 95+. All withdrawals are fully taxable as income in the year received. The Canada-US tax treaty extends the RRSP's exemption from U.S. dividend withholding tax to RRIFs as well. There is no maximum withdrawal limit.
Source
Income Tax Act s.146.3; Canada-US Tax Treaty Article XVIII