The Bank of Japan said Tuesday it made 11 sets of corrections to its statistics in less than three weeks during a bank-wide data review -- and it expects to make more.

The central bank has discreetly corrected the data on its Web site, and adjusted figures bear a footnote instructing concerned parties to call the BOJ for details. The errors have so far been "minor" and do not require official announcements, officials said.

The BOJ announced Tuesday that it discovered miscalculations had been made involving the average outstanding reserves kept by private-sector banks at the BOJ over the past five years.