Free market tonnage percentage cherries means that proportion of cherries handled in a crop year which are free to be marketed in normal commercial outlets in that crop year under any volume regulation established pursuant to Sec. 930.50 or Sec. 930.51 and, in the absence of a restricted percentage being established for a crop year pursuant to Sec. 930.50 or Sec. 930.51, means all cherries received by handlers in that crop year.