It accounted for roughly two-fifths of total exports of goods and services in 2016, thus exceeding the fisheries, which have been the foundation of the Icelandic economy for centuries. According to the Icelandic Tourist Board, the recent proportion of all international visitors who arrived in Iceland during the three summer months (June, July and August) has decreased from about 50% to 35%, while the increase of visits has been particularly high in the winter months, creating a whole new challenge for managers regarding nature protection and safety issues at the destinations. The geographical distribution of travellers is highly concentrated at a few destinations, such as Gullfoss, Geysir, Ringvellir and Jokulsarlon.