Comparison of investment in stores inventories to annual issues shall be made to assure that minimum inventories are maintained for the support of programs. This comparison may be expressed either as a turnover ratio (dollar value of issues divided by dollar value of inventory) or in the average number of month's supply on hand. Turnover or number of month's supply is calculated only on current-use inventory. Performance goals, i.e., a six months investment or a turnover ratio of 2.0, shall be established for each stores using activity. It is recognized, however, that extenuating operating circumstances may preclude the achievement of such objectives.