Many PV systems exhibit a poorer performance as is to be expected using installed peak power. Performance ratios of 'reasonable' systems have experimentally been determined in the range of 60%-85% of STC (=standard test conditions) performance. A significant part of the losses is due to the performance deviation of PV modules from their rating at STC due to the outdoor conditions (realistic reporting conditions, RRC). To overcome the problems in module performance evaluation and to assist system sizing, a realistic PV efficiency map of America is presented. In a similar way as the European radiation atlas for solar irradiation, this RRC market survey of PV modules gives detailed information on module performance at many sites for various installation conditions.