The stock of capital in European Community agriculture
估算了欧共体农业中建筑物、机械和运输车辆的资本存量，基于过去投资累积并调整资产报废和效率损失，采用矩形双曲线模型近似效率与年龄的关系。
This paper presents estimates of capital stocks of buildings and machinery and transportation vehicles in European Community agriculture. The capital stocks are the cumulation of all past investments adjusted for discards of worn-out assets and loss of efficiency of assets over their service life. Asset discards are calculated based on an assumed mean service life for a group of assets and a distribution of actual discards around this mean service life. Efficiency loss is assumed to be a function of age. The function relating efficiency to age of the asset is approximated by a rectangular hyperbola concave to the origin. This rectangular hyperbola provides a general model incorporating several of the commonly used forms of depreciation as special cases.