I analysed this questions recently together with a colleague in the paper "Long Term Trends in Steel Consumption" (Downloadable at ResearchGate, forthcoming in Mineral Economics). Quite often, intensity of use (IoU) of steel is defined as Steel consumption per unit of GDP. We think this definition to be problematic, since the IoU highly depends of on the concept of internationally comparable GDP employed. We, therefore, perfer to look at steel consumption per capita. We find a bell-shaped curve with steel sonsumption per capita reaching its maximum at the per capita income of about 30.000 $ (in PPP).However, in our paper we also hint at a second problem: IoU is typically measured only for apparent steel consumption, whereas indirect steel imports, i.e. steel incorporated in imported cars or in machines aree neglected. Therefore, IoU is most probably under estimated for small countries which tend to import steel intensive products instead of producing them.