The essential feature of the olive oil market lies in the irregularity of harvests and in that of supplying the market; these irregularities result in fluctuations in the value of production and in the instability of prices and of receipts from exportation, as well as in considerable differences in the incomes of producers.
The proportion of oil produced which enters into world trade is small, most of it being consumed in the producing country. However, consumption in a number of countries has been decreasing, and there have been temporary surpluses. There are a number of difficulties in preventing the deterioration of olive oil in storage.
Olive oil production is the main source of income of millions of families who are wholly dependent on the measures taken for maintaining and developing the consumption of its products. Control of production is made more difficult by the long time span involved. The tree begins to produce at ages varying from 6 to 15 years and reaches maturity between the age of 80 and 120 years. About one-and-a-half million metric tons of olives are produced annually. The largest growers, in order, are: Italy, Spain, Greece, Turkey, Tunisia, Portugal and Morocco, some of whose export ratios are very high in relation to domestic consumption (for example, Tunisia, Morocco, Spain). All of the above are exporters of olive oil, to which may be added Argentina, Algeria and France.