not available for the whole 1965-95 period. The most complete are sixteen series for wheat based on different origins and destinations published in the FAO yearbooks, including wheat freights from US gulf ports to Japan and Rotterdam, and to I]ndia in some years( see Annex 1). These have been used to estimate freight rates for wheat and also as a basis for the estimates for some of the other crops. For other commodities, actual freight rates were available from Indian sources for a few years, and we used the international wheat freight series or other series to index these forwards and backwards to other years. Various other approximations and calculations are explained in the individual background papers. Among the complications that should borne in mind in interpreting these estimates is that for many commodities in most years they are hypothetical, since there was no trade actually occurring. However the level of freight rates depends among other things on the volume of trade and the efficiency of ports. In using published international freights as a basis for estimating Indian freights, we generally assumed implicitly that if trade had occurred, it would have been in large ships in large volumes, and that port capacities would have been adjusted accordingly without, for example, port bottlenecks and long waiting times for ships which would be reflected in freight rates 7

# _Port costs_

Estimates of port costs -mainly the cost of unloading imports or loading exports, but also other expenses such as customs clearance and storage- were made in the original commodity studies, but usually for one or a few years in the 1 980s only. For a number of commodities there were no exports or imports, and it was assumed that port costs would be the same as for other similar commodities. Partly for the same reasons, we were also unable to find actual port costs for the 1970s and earlier. To project the observed port charges forward to 1995 and back to 1971 we used the public sector emolument index, on the reasoning that this would approximate labor costs in the ports, which are managed by public sector port authorities. This index is not available before 1971, and for these years we used the consumer price index for industrial workers. The two together give a consistent series to project port charges, and are shown in Annex 2.

# _Marketing costs_

Moving commodities to be exported from port cities or to compete with imports there or elsewhere also involves marketing costs which include interest charges, handling expenses, storage charges, overhead expenses, miscellaneous expenses arising out of transit and storage losses, and wholesale distribution margins. These costs vary considerably by year, by season and by crop. In the case of each crop, the general treatment follows that adopted in the original commodity studies. However some general rules of thumb have also been used. In particular, based on the study by Sharma and a review of a number of studies by Gulati et al (1990)8, in the case of foodgrains and oilseeds in the 1 980s, we have taken marketing costs to consist of an interest charge for two months at an 18 percent rate applied to the procurement price, plus Re 1 per quintal to represent other marketing expenses. To project these estimates forwards and backwards, we calculated the average of these marketing costs expressed as a percentages of the prices of each commodity during five years in the 1980s. These percentages were applied to

> 7 The significance of this assumption is apparent from reports of port bottlenecks which were creating long waiting times for ships when substantial exports of wheat and rice started in the mid 1 990s. 8Gulati, Ashok with James Hanson and Garry Pursell. 1990. "Effective Incentives in Indian Agriculture: Cotton, Groundnuts, Wheat, and Rice".

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