PV module retail price index, 2003–2012. The figures presented are average retail prices in Europe and the USA based on a monthly online survey. They encompass a wide range of module prices, varying according to the module technology (with thin film modules generally cheaper than c-Si), the module model and manufacturer, its quality, as well as the country in which the product is purchased. For example, in March 2012 average retail module prices were 2.29 $ per Wp in the USA and 2.17 € per Wp in Europe, respectively, but the lowest retail price for a c-Si solar module was 1.1 $ per Wp (0.81 € per Wp) and the lowest thin film module price was 0.84 $ per Wp (0.62 € per Wp). Source: ref. 41.