What percentage of the world's olive harvest winds up in martinis?

Much of the world's olive harvest is pressed to make olive oil. Olives are a common ingredient on pizza, in spaghetti sauce, and in baked bread. Olives are served for breakfast, lunch, and dinner on the Baltic Peninsula and throughout the Middle East. The most popular drink in these areas is anise flavored Ouzo, Mastika, which are not garnished with olives, or (in the Middle East) no alcohol at all.

To appropriately answer your question we need to match up global olive production with the production of gin and vodka--the two primary martini alcohols garnished with olives. Although California produces about 99% of the olives grown in the US, it only grows about 1% of the world's production. Throughout Russia and Eastern Europe vodka is typically imbibed alone, without being mixed. The martini cocktail with olive, therefore, is primarily most popular in Western Europe and the United States.

Armed with this information I believe we can safely estimate the amount of olive harvest ending up in martinis to be substantially less than 1%.