Year-end level from BEA, Fixed Asset Table 4.1 Current-Cost Net Stock of Private Nonresidential Fixed Assets by Industry Group and Legal Form of Organization; line 30, corporate nonfinancial, Structures. Other quarter's levels are derived from year-end level, plus the quarterly unadjusted flow calculated as gross investment (FOF series FU105013063) less depreciation (FOF series FU106330063) and less other volume changes (FOF series FU105404363), plus an estimate of capital gains based on NIPA, table 1.1.4 Price Indexes for Gross Domestic Product, line 10, Nonresidential, Structures.
