of the island's surface to rise out of the water by a reported 8 to 14 centimetres. Scientists say that the injection of molten rock was equivalent to 20 years' worth of regular activity. Climate Santorini has a semi-arid climate (BSh in the Köppen climate classification) with Mediterranean characteristics. Total rainfall averages per year. In the summer season, strong winds can also be observed. Economy Santorini's primary industry is tourism, particularly in the summer months. Agriculture also forms part of its economy, and the island sustains a wine industry. Agriculture Because of its unique ecology and climate - and especially its volcanic ash soil - Santorini is home to unique and prized produce such as the Santorini cherry tomato. Viticulture, whose history goes back to prehistoric times, could not remain unaffected by the rapid increase in tourism, where there was a gradual decrease until 1997. Although today viticulture is the most important sector of agricultural production in Santorini and now traditional throughout Greece . Wine industry The island remains the home of a small, but flourishing, wine industry, based on the indigenous Assyrtiko grape variety, with auxiliary cultivations of Aegean white varieties such as Athiri and Aidani and the red varieties such as Mavrotragano and Mandilaria. The vines are extremely old and resistant to phylloxera (attributed by local winemakers to the well-drained volcanic soil and its chemistry), so the vines needed no replacement during the great phylloxera epidemic of the late 19th century. In their adaptation to their habitat, such vines are planted far apart, as their principal source of moisture is dew, and they often are trained in the shape of low-spiralling baskets, with the grapes hanging inside to protect them from the winds. The viticultural pride of the island is the sweet and strong Vinsanto (), a dessert wine made from the best sun-dried Assyrtiko, Athiri, and Aidani grapes, and undergoing long barrel aging (up to twenty or twenty-five years for the top cuvées). It matures to a sweet, dark, amber-orange unctuous dessert wine that has achieved worldwide fame, possessing the standard Assyrtiko aromas of citrus and minerals, layered with overtones of nuts, raisins, figs, honey, and tea. White wines from the island are extremely dry with a strong citrus scent and mineral and iodide salt aromas contributed by the ashy volcanic soil, whereas barrel aging gives to some of the white wines a slight frankincense aroma, much