Cape Verde has few natural resources. Only five of the ten main islands (Santiago, Santo Antão, São Nicolau, Fogo, and Brava) normally support significant agricultural production, and over 90% of all food consumed in Cape Verde is imported. Mineral resources include salt, pozzolana (a volcanic rock used in cement production), and limestone. Its small number of wineries making Portuguese-style wines have traditionally focused on the domestic market, but have recently met with some international acclaim. A number of wine tours of Cape Verde's various microclimates began to be offered in spring 2010.