Although the production of it was successful, the Republic only allowed exportation to Venice. Statistics for the years 1766–70 indicate 1,905,917 olive trees on Corfu, 113,161 on Zante, 38,516 on Cephalonia, 44,146 on Lefkada and 31,884 on Cythera. Nevertheless, raisin exports were the most important export of the islands during the Venetian rule. By the early 18th century Zante, Cephalonia, and part of Ithaca had become a major centre of the currant trade. Because of the fierce competition in the raisin trade between Venice and the United Kingdom, Venice prohibited the free export of raisins from the islands. Another measure was the , a heavy export tax for foreign ships. The currency of the islands during Venetian rule was the Venetian lira, as in Venice. There was a special issue for the Islands; the observe side of it has the complete or shortened inscription CORFU/CEFALONIA/ZANTE in three lines. The reserve depicts the winged and haloed lion of Saint Marc in a front view, holding the book of the Gospel in his fore-paws. The Ionian Islands formed part of the Venetian maritime trade route to the Orient. Demographics When the central Ionian Islands were captured by Venice their population was very low and Ithaca was completely uninhabited. To address this problem, a small colonisation to the islands took place. Catholic Italians from (later called Corfiot Italians) and Orthodox Greeks from the were transferred to the islands as part of the colonisation. The population eventually increased: in 1765–66 it had reached 111,439; in 1780, the population was 150,908. Fourteen years later, there were 155,770 inhabitants throughout the islands. These are some figures concerning the population of each island during the Venetian period: Language and education During the Venetian period all public acts were drawn up in the Venetian language, the official language of the Government. Greek remained spoken by the peasantry whereas Venetian was adopted by the upper class and it was generally preferred within the towns (like in Corfu city, where nearly all the population spoke the Veneto de Mar). Thus, the Venetian language became, if not the common language of the Ionians, at least the prestigious language. The Venetians did little in the area of education, mainly due to the fact that schooling was not considered a responsibility of the state at that time in Europe but a private matter. Some authors believe that this was done intentionally by Venice,