What is the collection period calculation?$$

ANNUAL BALANCE SHEET ($ Thousands) 31-Dec-15 31-Dec-16 ASSETS Cash & Short-Term Investments $17.11 $25.05 Net Receivables $1.62 $1.84 Inventories $42.72 $39.68 Prepaid Expenses $0.00 $0.00 Other Current Assets $3.38 $2.93 Total Current Assets $64.84 $69.49 Gross Plant, Property & Equipment $63.75 $58.28 Accumulated Depreciation $36.16 $32.61 Net Plant, Property & Equipment $27.58 $25.67 Intangibles $5.88 $6.01 Other Assets $6.16 $5.81 TOTAL ASSETS $104.47 $106.98 LIABILITIES Long Term Debt Due In One Year $0.00 $0.00 Accounts Payable $10.59 $11.91 Taxes Payable $1.87 $2.01 Accrued Expenses $7.19 $6.91 Other Current Liabilities $1.88 $1.85 Total Current Liabilities $21.54 $22.67 Long Term Debt $6.95 $19.79 Deferred Taxes $1.16 $2.32 Other Liabilities $3.04 $2.43 TOTAL LIABILITIES $32.68 $47.21 EQUITY Common Stock $0.07 $0.06 Capital Surplus $27.25 $24.31 Retained Earnings $73.89 $61.10 Less: Treasury Stock $29.42 $25.71