Role of the Colonial Trade in the Industrialization of Europe

The idea that the colonial trade was crucial to the industrialization 
of Europe is (still) a commonly accepted claim  among world-system 
followers - this, despite the significant statistical evidence 
already put forward against this claim. One of the strongest, 
empirical challenges goes back to O'Brien's article "European Economic 
Development: The Contribution of the Periphery" (EHR 1982), an 
well-known article which, notwithstanding Wallerstein's response to 
it in the same journal (1983), still awaits a serious answer from ws 
scholars.  Among the many claims of this article is the highly 
damaging one that, if we agree with  Bairoch's data that commodity 
trade between core and periphery amounted to no more than 4% of the 
aggregate GNP for Western Europe, and if we assume that core 
capitalists made such large profits as 50% on the trade turnover, and 
that they re-invested as high as 50% of their profits, the colonial 
profits re-invested would have amounted to only 1% og GNP, or 10% of 
gross investment.