Seasonally adjusted flow from BEA, NIPA, Table 1.12, line 48, Inventory valuation adjustment. Prior to 2007, unadjusted flow from BEA, NIPA, Table 8.6, line 5, Inventory valuation adjustment. Seasonal factors are calculated as the seasonally adjusted flow at an annual rate, divided by four, less the unadjusted quarterly flow. Series has no levels.