The main assumption used in creating these import matrices is the “proportionality” assumption, which assumes that the share of imports in any product consumed directly as intermediate consumption or final demand (except exports) is the same for all users. Indeed, this is also an assumption that is widely used by national statistics offices in constructing tables. This hypothesis is acceptable for industrialized countries, where there is little product differentiation between what is produced for export and what is produced for the domestic market.12 It is less convincing, however, for developing countries as the import content of exports is usually higher (and much higher for processing) than the import content of products destined for domestic consumption. Improving the way that imports are allocated to users will form a central part of the future work of the OECD and WTO as well as the international statistical system, as stated in the Global Forum on Trade Statistics, in Geneva in February 2011.13 Indeed, the tables included for China capture this heterogeneity by breaking each industry into three categories: firms that provide goods and services for domestic markets only, processing firms and other exporters.